Mixing Ferts Dry and Wet

DLoja · Mar 10, 2015

I wanted to double check what I feel I've read after doing some searching. I am new to dry ferts and want to make sure I don't mix anything that shouldn't be mixed, as well as check about premixing them with tank water / tap water for a drip system or such. Here is what I have:

Potassium Nitrate - KNO3

Monopotassium Phosphate - KH2PO4

Potassium Sulfate - K2SO4

Calcium Sulfate / Gypsum - CaSO4

Magnesium Sulfate / Epsom Salt - MgSO4

Ferrous Gluconate / Iron(II) Gluconate - C12H24FeO14

Plantex CSM+B

Seachem Prime / Safe

I believe it's best to wait a day after a water change when using a conditioner that detoxifies metals, such as Seachem's Prime / Safe, though many say it doesn't matter much as it can only bind a little bit of metals compared to what's being dosed. I figured I'd typically just not dose that day, but that means the water will have much less nutrients in it than normal that day rather than keeping it at a more steady level, so maybe I'll dose anyway...?

So what can be stored together dry for quick addition (once happy with ratios)? Sounds like iron should stay separate / with trace to avoid cloudiness? So can the macros and gh boost all be mixed together if desired? Can I mix the iron in w/ the CSM for extra iron?

What about in solution? If I wanted to set up a drip system or pump can I make a months worth and have all macros and gh boost together, and a separate one for trace / iron?

Will they all last that long without precipitating out of solution or causing any adverse reactions? I believe I read to add some excel (20 mls per 500 mls) to the trace to help it last out of the fridge without developing mold or clogging the lines.

I also figured I could just mix this with some tank water I grab out rather than having to dose tap water with Safe and then wait 48 hours before mixing with ferts, though if they last in solution a month or more that wouldn't be too much of a problem.

Thanks for the help on this new adventure!

rjordan393 · Mar 12, 2015

Most fish keepers need to use a conditioner. If you have chlorine or chloramine in your water supply, then you should use a conditioner during a water change or pre-treat the water before the water change. Some conditioners will also detoxify metals such as copper and iron (some do not) but only if their concentration does not exceed EPA standards. One manufacturer states that their product will detoxify metals that are normally found in public water supplies. So this means public water suppliers are following EPA Standards. So the first thing you need to do is find out what is in your water supply. Then that determines what type of conditioner you need. Those who get their water from wells should be more concerned. Some fish keepers need to use ro or ro/di water systems to purify their water, then need to add some minerals back into the water.

I dose my macro's and micro's all separately and each is pre-mixed in distilled water in a 500 ml bottles. This is what I recommend. I know some pre-mix their macro's but I do not know how this works long term. The same goes for GH booster. I see no harm in adding extra iron in CSM but do so only if you know you need it. I keep my CSM and KNO3 refrigerated to maintain their quality. Do not use tank water or tap water for use in preparing stock solutions. There are too many things involved that can make your stock solution go bad. Use ro/di or distilled water for your stock solutions.

RBurtchett · Mar 12, 2015

rjordan393 said:
if you know you need it. I keep my CSM and KNO3 refrigerated to maintain their quality.

Why refrigerated? I have not heard this before. Some seem to have issues with CSM molding but I do not. I use a 500 ml stock solution in less than a month. Robert

rjordan393 · Mar 12, 2015

There was a discussion about this some months ago and I believe Tom Barr recommended it. I do not recall the reasons but it may have something to do with the temperature the ferts are stored at.

DLoja · Mar 12, 2015

Trace mix is often recommended to be either stored cold or with some Excel in it to stop the mold. The mold is harmless and can also be scrapped off, but it can junk up your lines if using a drip system or such. I've had an old bottle of Flourish lying around for years with no mold though, so I don't know.

I've never heard of refrigerating the nitrate so not sure there.

rjordan, you're saying you pre mix all your ferts separately with water? So half a dozen different bottles premixed with water but not each other?

I'm fairly confident that all the macros can be premixed for many months no problem, but I am trying to confirm that to be safe. I'm also wondering if a low dose of GH boost can safely be added to that macro mix as well though.

rjordan393 · Mar 13, 2015

Yes, I use separate 500 ml bottles for all the stock solutions of macro's and Micro's. Premixing dry macro's may or may not work. Each macro has its own weight; so how will you know that it will not settle out? When you use a measuring spoon, you cannot tell what ratio of KNO3 to KH2PO4 to K really is.

Now pre-mixing all three macro's in solution creates a similar problem. If one uses Wet's calculator, each macro is added to a certain amount of water. I am going to use the amount of KNO3 to 500 ml of distilled water that I make up for my stock solution as an example. I add 75.2 grams of KNO3 to my bottle and now Wet's calculator tells me for 64.9 gallons of tank water, that a 30 ml dose of my stock solution will give me 11.3 ppm NO3 as a result. Now I make up my KH2PO4 and K stock solutions in a similar way. "Now here is the point"....if I were to add all three macro's together using a 1500 ml bottle, then that screws up Wet's calculator because you have diluted the original 500 ml of KNO3 by 3 times and the same goes for the KH2PO4 and K. Now you do not know how much to dose of the stock solutions. Now let's assume I use wet's calculator again; but this time I use 1500 ml instead of 500 ml as my imput of distilled water. The calculator will give me the correct dose to add to my tank to get the required result for NO3. But there is a problem; If I dose 90 ml to get the correct amount of NO3 as a result, then what do I do if I only needed 50 ml of this same solution to get the required result for PO4. Or if I needed 130 ml of this same solution for K? I think one will have to be a math genius to figure it all out. For me, it is not worth the trouble. Do yourself a favor and keep all fertilizers in their own containers.

Tug · Mar 13, 2015

At some point, from all the gallons of stuff, I had three, one gallon bottles. When I do make solutions of KNO3, I keep it singular and it needs 24 hours to dissolve completely - 15 tablespoons / 1000 mL distilled water. If you add it dry, directly to the tank, it desolves quickly. For larger tanks, dry KNO3 if needed, between, 1/4 - 3/4 tsp per 100 liters of tank, 2-4 times a week - depending on your tank.

From my tap, phosphate levels are around 2 ppm but I like that. I also add what I call modEI, adding KH2PO4 and K2SO4 into distilled water. I might be off by the calculator, in my case I have a good amount of phosphate so, I wanted K+. For small tank (100 L.), I've found it easer to dose mixed as a stock solution but I mix a gallon at a time with Excel (Glutaraldehyde) to clean the bottles and to the stock solution as a anti-fungal.

I had bad experience storing CSM+B, using excel. Others say they have not. I add something to lower the pH of the stock and I add potassium Sorbate instead of Glutaraldehyde/Excel. I've never had a problem with concentrations of 55 grams CSM+B (4 Tbsp), with or without an additional, 2 Tbsp supplemental Fe/900 mL water.

Lowering the temp and the pH will slow or prevent most molds from forming. Who knows, all these years I've been preventing the benefits of mold and live bacteria with trace. I might just lower the pH next batch.

DLoja · Mar 13, 2015

rjordan393 said:
Yes, I use separate 500 ml bottles for all the stock solutions of macro's and Micro's. Premixing dry macro's may or may not work. Each macro has its own weight; so how will you know that it will not settle out? When you use a measuring spoon, you cannot tell what ratio of KNO3 to KH2PO4 to K really is.

Now pre-mixing all three macro's in solution creates a similar problem. If one uses Wet's calculator, each macro is added to a certain amount of water. I am going to use the amount of KNO3 to 500 ml of distilled water that I make up for my stock solution as an example. I add 75.2 grams of KNO3 to my bottle and now Wet's calculator tells me for 64.9 gallons of tank water, that a 30 ml dose of my stock solution will give me 11.3 ppm NO3 as a result. Now I make up my KH2PO4 and K stock solutions in a similar way. "Now here is the point"....if I were to add all three macro's together using a 1500 ml bottle, then that screws up Wet's calculator because you have diluted the original 500 ml of KNO3 by 3 times and the same goes for the KH2PO4 and K. Now you do not know how much to dose of the stock solutions. Now let's assume I use wet's calculator again; but this time I use 1500 ml instead of 500 ml as my imput of distilled water. The calculator will give me the correct dose to add to my tank to get the required result for NO3. But there is a problem; If I dose 90 ml to get the correct amount of NO3 as a result, then what do I do if I only needed 50 ml of this same solution to get the required result for PO4. Or if I needed 130 ml of this same solution for K? I think one will have to be a math genius to figure it all out. For me, it is not worth the trouble. Do yourself a favor and keep all fertilizers in their own containers.

Sorry rjordan, I still don't follow. Maybe it's because I am a math guy, but... it sounds like the way you currently mix each of your ferts is to figure out how much to put in a 500 ml container and then separately how many ml's to dose. To me that sounds awfully confusing, as i'd rather be dosing the same amount of each so I don't screw it up (which is what you'd do if mixing them together anyway). So instead you can calculate your mix to give you the right amount of each fert in a 30ml dose for instance (call it 1 oz). Now you're dosing 1 oz of each fert, and at this point it's easy enough to multiply the formula by a factor of x to fill your 500 ml container. But the point is, if you're dosing 1 oz of each fert you can then combine them all together quite easily. Either by putting those (for example we'll say 3) 3 mixes together and dosing 3 oz, or by looking at the math / how much you had to add of each fert to get your 500 ml. If I know how many grams of each was required to get my 500 ml container filled with a solution that has me dose 1 oz per dosing period, then I can just combine those all together in a single 500 ml bottle and continue to dose 1 oz. This however is dependent on there being enough liquid to fully dissolve the solution. If it's not you just increase the water and the dose by the same factor.

rjordan393 · Mar 13, 2015

Let me try to tackle this in another way. The numbers I am about to show as an example are my real stock solutions.

75.2 grams of KNO3 in 500 ml bottle of distilled water.

11.5 grams of KH2PO4 in 500 ml bottle of distilled water.

45.7 grams of K2SO4 in 500 ml bottle of distilled water.

Now that equals a total of 132.4 grams. If I were to try and dissolve that much in just one 500 ml bottle of distilled water, then I know that one thing will happen and maybe another.

Now my bottle is a former"Seachem" bottle and will easily hold 500 ml with some room to spare, then I know I can add 75.2 grams of KNO3 according to Wet's calculator. But when I try to add 11.5 grams of KH2PO4 and 45.7 grams of K2SO4 to this bottle, then the contents may spill over. The other thing is that there is a limit to solubility of the chemicals to dissolve in a certain amount of water and you could end up with a lot of solids in your container. So even if you went to a 1500 ml bottle and multiplied 132.4 grams by 3, you would still end up with the same result as above. And the effects of dilution have not been factored in and I have no idea if that can be accomplished. You can test this out for yourself. Take a 20 or 30 ml bottle and add about 5 ml of sugar. Now add 10 ml of water and shake it up. if it all dissolves, then by adding more sugar, you will soon reach a point whereas the solubility of sugar ends and will not further dissolve.

I suspect those who mix their ferts in one container are just guessing how many ppm of each parameter they are dosing.

I like the idea of separate containers because if I made a mistake in making a stock solution, I can easily correct it or if for some reason it goes bad, then I just toss it out and make up another without the expense of losing the other two parameters.

if someone on this forum knows how to mix three macro's to give a desired result for each parameter, then please us know.

DLoja · Mar 13, 2015

It's not hard to do, but you left out how much of each of those 3 solutions you dose each time. For a real world example why don't you let me know how much you dose of each and I'll do the math for you.

Also, I think you're a bit confused as far as dilution goes.

rjordan393 said:
So even if you went to a 1500 ml bottle and multiplied 132.4 grams by 3, you would still end up with the same result as above.

If you're using said 132.4 grams of total solids but it's too much to fully dissolve into solution with 500 ml of water then when you increase the water to said 1500 ml you would still only use the same 132.4 grams of total solids and the difference would be that you just dose 3 times as much of the final solution. Otherwise you're not making a dilution, you're just increasing the total volume of the same solution.

I can do the math easy enough, what I was trying to double check with others is that the chemicals are stable together both dry or in solution. While I know that plenty of people premix ahead of time, I just wanted to confirm one last time while spelling out exactly which chemicals are being used. I'm pretty sure they're the same ones since they are pretty standard, but was hoping to confirm.

Also, by no means am I trying to convert you or anyone else in the way you dose. I just know that I'd rather do as much as I can up front and make dosing that much simpler. Even if I decide not to do a drip system or such I'd rather have them mixed to my ideal ratio that's been working for me so I only measure and add one thing rather than 3. My 9 month old keeps me busy enough as it is. I will always keep an amount of each chemical separate if my ideal ratio no longer becomes ideal or I decide something needs a little boost, but to have as few solutions to measure out and dose each time is the goal.

Thanks for the replies!

rjordan393 · Mar 13, 2015

Quote: If you're using said 132.4 grams of total solids but it's too much to fully dissolve into solution with 500 ml of water then when you increase the water to said 1500 ml you would still only use the same 132.4 grams of total solids and the difference would be that you just dose 3 times as much of the final solution. Otherwise you're not making a dilution, you're just increasing the total volume of the same solution. Unquote.

Ok, that will work if you are going to use the EI method of dosing. But remember what is stated at the top of the page when using that method. And that is high light and well planted aquariums that EI is recommended. So you mix your ferts and then test before your next water change and you find out that your stock solutuion needs correcting on one or more parameters. Now what do you do with your stock solution? Do you dilute it or do you add some dry form of ferts to adjust your stock? For me no thanks. I am sticking to separate bottles and dose them according to my test results. I have 64.9 gallons in my aquarium and I find that dosing at the EI recommended 20 to 40 gallon capacity at 3 times a week gives me a bit more NO3 then I desire. I only have 6 plants and all are Lugwiga repens. So I need to adjust my dose and my separate bottles allows me to do this or dose 2 times a week. I am still working on which way to go because as of now, I am removing my gravel and going bare bottom and I will use a sand filter as my bio-filter and not depend on what little plants I have to perform this function.

I have 10 years experience with keeping a marine tank and 4 years with fresh water with plants and I do find it hard to accept the new school of thought when I attended the old school of thought.

DLoja · Mar 13, 2015

Hey rjordan, I still think we're somehow miscommunicating here. That section you quoted has nothing to do with dosing EI method or dosing extra or anything. It's just explaining how dilution works. Even if we're only talking about 1 fert, say KNO3, and you try to put 75.2 g of it into 250 ml of water so you can dose 15 ml of that final solution each time, but it won't fully dissolve! Well, then you can simply double the water to 500 ml and dose 30 ml of that solution each time. The dose of KNO3 going into the tank does not change! You're adding 4.512 g of KNO3 per dose either way, the rest is just water. If you wanted to dissolve it into 1000 ml of water you would then dose 60 ml of that solution and you'd still be dosing 4.512 g of KNO3 per dose.

If you're happy with your system and it's working out for you that's awesome, keep at it! I, however, know what I want to do but am hoping to get some confirmation that those chemicals will coexist happily.

I've been keeping freshwater tanks for over 12 years, and am researching different areas of it all the time, and I know what you mean as far as old and new information. I'm just trying to clarify a few things so everyone can make their own informed decisions. Unfortunately I've looked around, and many of the different forum posts that are quoted for reference to help people with their dosing that I've found have at least a couple mistakes in them. I just found a great reference post on making your own dKH solution for a drop checker (http://www.plantedtank.net/forums/showthread.php?t=42429) but that has at least 2 mathematical errors that I saw. One of which is a minute discrepancy so doesn't really matter for our purposes, but the other is a big mistake if anyone blinding makes a 5 dKH solution off of what was stated.

Anyway, if anyone else out there mixes their macros together with or without a tiny bit of GH boost, I'd love to hear from ya!

Thanks,

David

Tug · Mar 13, 2015

I have and I don't think you will find many people do what you're suggesting. I would like to apply the idea to mixing the dry NPK, for single dosing, directly into the tank. I know it can be done. It's a question of calculating the dose, as you mention. If you don't mind a PM, I'm looking for help with that calculation.

The solubility issues with KNO3 are no more then they take up a limited space, fitting GH booster into one solution with KNO3, you would now have to raise the dose and that becomes a pain compared to dosing the GH, say 1-2x week with the water changes.

There may have been some problems with PO4, I can't remember. But with K2SO4 and KH2PO4, it's hard to add more then 20g KH2PO4 to 1000 mL of water, when I add 58 g of K2SO4. For every dose it provides 0.8 ppm PO4, it provides 1.3 ppm K+ from the same dose. I might change the rate some but you see the point. It limits the PO4 per mL dosed.

DLoja · Mar 13, 2015

Hey Tug, PM sent and hopefully I cleared up your math problem. If you're looking for something else just let me know!

From what I can tell anyone using a drip system or pump is breaking it up into 2 sets of solution. 1 for NPK and one for Trace. I haven't heard anyone specifically mention the addition of a bit of GH boost, but many don't list out their actual chemical ingredients. I just figure since it will slowly get used up I might as well slowly add it back in, same as other ferts. Plus of course more on water change day.

Solubility is obviously something I'll have to play with if I decide to premix wet, but that's easy enough. I've looked at and calculated approximate solubility of each substance at my ave room temp of 75f and my altitude of practically sea level (30 ft), but that doesn't mean it will mix easily or quickly, I just sorta got caught up in it.

So really once I decide to pull the trigger I'll have a jumping off point and add extra water as needed. Just means my final ml of solution dose will get bigger, no problem.

rjordan393 · Mar 14, 2015

I had some questions regarding chemistry and joined this forum: http://www.chemicalforums.com/

When I told them I did not have a chemistry background, they placed my questions in a topic called "Citizen Chemist". They were most helpful. If there is a problem mixing chemicals either dry or wet, they will know. Give them all the details such as volume, amount of chemicals and their ppm. They will be able to tell you if anything will happen short or long term.

DLoja · Mar 14, 2015

Thanks rjordan, I just posted over there and will let everyone know if I get any answers.

rjordan393 · Mar 15, 2015

I posted also. Your post must have been buried under another users post and I did not see it. But take a look at one of the replies when I asked about possible problems when mixing chemicals in solution that have different strengths and/or volume changes. Only a chemist would understand the reply. I should have mentioned that I am not a chemist. But if you are familiar with chemistry, there is a link for a calculator that may help. But its good to use for 30 days, then you have to purchase it to continue.

RBurtchett · Mar 15, 2015

Ok, I read both of your postings. And short answer is yes the macros & GH can be mixed provided you do not add the micros or iron. Use RO or distilled water due to PH. The dry or wet preparations would be fine (though settling would be an issue in my opinion do to different weight and crystal form.) The simplest solution would be to adjust the concentrations of each chemical dose to be the same volume dose when wet to 1 ml per 37.85 l (10 gal) with a 500 ml solution volume. Weight out said dry chemicals (-micros & iron), put them in the same graduated container and fill with RO or distilled H2O to 500 ml. If this doesn't fully dissolve then add additional H2O to the 1000 ml level and adjust your dosing to 2 ml per 10 gallon. Robert

DLoja · Mar 15, 2015

Hi Robert, that's exactly what I'm thinking, all of it! The only thing I don't get is when you say:

Use RO or distilled water due to PH.

What do you mean due to PH? I'm still trying to figure out if RO/DI water is necessary, so if you have an explanation I'd love to hear it.

Thanks!

David

DLoja · Mar 15, 2015

Hey rjordan, I responded to your post on the chemistry forum, but in case it will help anyone else clear up the dosing math a bit, here it is:

75.2 grams of KNO3 to 500 ml distilled water. 30 ml dose of this to 64.9 gallons of aquarium water results in 11.3 NO3 ppm added.

11.5 grams of KH2PO4 to 500 ml distilled water. 30 ml dose of this to 64.9 gallons of aquarium water results in 1.96 ppm PO4 added.

45.7 grams of K2SO4 to 500 ml distilled water. 45 ml dose of this to 64.9 gallons of aquarium water results in 7.51 ppm K added.

So can these chemicals be mixed together either dry or in solution and still give the same results?

All you need to do first is get your doses to be the same. Since your KNO3 and KH2PO4 doses are already that same at 30 ml, lets just adjust your dose of K2SO4 to 30 ml as well.

Right now you are dosing 45 ml of your 500 ml total, or exactly 9% (45/500). 9% of your 45.7 g means your ideal dose is 4.113 g of K2SO4 each time. Since we want to get that dose to 30 ml, or exactly 6% (30/500), you will have to increase the amount of K2SO4 added to your 500 ml total by 50% or in other words, add 68.55 g, which when dosing 30 ml or 6% gives you the same desired 4.113 g per dose.

Now that you've adjusted your K2SO4, just pour them all together. The key is that to keep dosing 30 ml you'll have to fit it all in the same 500 ml of water. If that's not enough water to dissolve it all, then trying dosing 60 ml of a total 1000 ml solution, or 90 ml of a 1500 solution. You're only changing the amount of total water to dissolve the same amount of ingredients into while keeping your dosing % the same (6% in this case). Make sense?

Good Luck,

David

Mixing Ferts Dry and Wet

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