Fish bioload and dosing, how's my regime sound?

rich815

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Jun 26, 2008
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It seems based on some testing I've done that my Nitrates are pretty steady between 10-20ppm and my Phosphates at 3-5ppm. All that with no macro ferts added and apparently coming from my fish bioload (I am a bit high). Therefore what I'm doing for my 72 gal as a dosing regime right now is adding Potassium with Seachem liquid Potassium (2 capfuls - 10 ml) 3x a week and CSM+B Plantex (mixed at a rate of 2 T in 500ml of water then dosed also at 10ml 3x a week) on alternate days to the Potassium. When I run out of Seachem liquid Potassium I plan to dose with K2SO4 at similar levels. I also add 1 T of Barr's GH Booster after a 50% water change on the weekend. This keeps my GH at about 2-3ppm. My KH seems to stay steady at 4-5. And my pH at 6.8-6.9. My CO2 (pressurized), using an in-line reactor, seems at 30ppm based on my lime-green drop checker water (using 4dKH water). My lighting over my 72 gal is two 2x54W Hagen T5 HO fixures on for about 9 1/2 hours a day (12 noon to 9:30pm). Substrate is a an inch or so of SoilMaster Select (new, about a month now) over a couple inches of Flourite and sand (my older substrate about a year old) I place 4-5 Flourish root tabs in various places in the substrate every month or so.

It just seems with the fish load it keeps my Nitrates and Phosphates at "decent" levels that it would be too much to dose those as well using dry ferts. My plants seem to be doing pretty good so far. Some algae (some brown just under the gravel line on the glass, some occasional GSA on the glass and a few leaves, and some BBA here and there) but nothing overwhelming.

Anything I'm missing with this logic?
 

ceg4048

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Hi,
I probably wouldn't trust any NO3 or PO4 test kits as far as i could throw them. It's bound to get you into trouble. If the leaves which have GSA are anything other than anubias leaves (which always seem to collect GSA regardless) I would suspect low PO4 and would start dosing it immediately.

If your CO2 were adequate you would have absolutely zero BBA, so that means either flow or CO2 is suspect. Does the CO2 come on before the lights come on? If not you may want to consider adjusting the timer so that the gas turns on 1-2 hours before the lights. You may also need to increase the injection rate and consider increasing flow via filtration upgrade and/or powerheads.

Cheers,
 

rich815

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Jun 26, 2008
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Thanks for your thoughts ceg4048. My CO2 is strong at about 3 bubbles/second. Though I guess I could increase it a bit as the DC is not yellow yet. I have an eheim 2026 and 2028 running with two outflow bars. Perhaps adding a power flow head might help some dead spots though the flow seems pretty good with a decent amount of plant sway. So, even with a strong deep blue from my API phosphate kit and high fish load you think I should be popping some more phosphate in there eh? How about Nitrates? Should I just do a straight full EI regime with good NPK macros 3x a week alternating with the CSM+B Plantex for the micros 3x a week alternatively just to play it safe? After all with my once a week 50% water change nothing would build up too much. And worries over some limiting factor would be gone....thoughts?
 

VaughnH

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Some of us (not including me) enjoy testing water and figuring out how to adjust the fertilizer dosing to maintain a specific range of each nutrient in the water. Others (including me) don't trust test kits anyway, and don't enjoy testing or trying to adjust nutrient levels. This latter group is the one that Tom's Estimative Index method of dosing is aimed at. Since I am in that group I have to recommend that others, including you, follow that method. But, I admit that many people are successful with other nutrient dosing schemes, including lots of testing and adjusting.

If you do decide to continue as you are, at least spend the necessary time to calibrate your test kits carefully, so you can rely on them. Uncalibrated test kits are just a form of guessing.
 

rich815

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Jun 26, 2008
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Sounds great. What has confused me is some who have said I should go the EI route but adjust for bioload from fish. But I thought the whole concept of EI was to not have to worry about that and how it's hard to over-fert, especially with the big weekly water change.

I hate to test, except maybe CO2 with the DC (by the way thanks Hoppy, using your past posts on making 4 dKH water it's working great!). I guess the most vital concern would be over-dosing and have too much Nitrate which can be bad for fish, no? Or would following the EI method for my size tank, AND the weekly water change, generally keep me from going too high on Nitrates so as to not worry about it too much?
 

rich815

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Jun 26, 2008
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Ok, I'm going to go straight EI in my 72 gal and ignore my cheap Nitrate and Phosphate testing kits and the levels they are giving me. I'll keep the CO2 strong (and get a small power head to move things in some slight dead spots), do 3/4 tsp. KNO3 and 3ml of Fleet 3x times a week and CSM+B Plantex 3x/week on alternate days to the KNO3/Fleet days. 1 tsp. of GH Booster after the once/week 50% water change and 1 tsp. mid-week. Will do this for 3 weeks and observe....
 

VaughnH

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rich815;27127 said:
Ok, I'm going to go straight EI in my 72 gal and ignore my cheap Nitrate and Phosphate testing kits and the levels they are giving me. I'll keep the CO2 strong (and get a small power head to move things in some slight dead spots), do 3/4 tsp. KNO3 and 3ml of Fleet 3x times a week and CSM+B Plantex 3x/week on alternate days to the KNO3/Fleet days. 1 tsp. of GH Booster after the once/week 50% water change and 1 tsp. mid-week. Will do this for 3 weeks and observe....

Ah! One more convert to EI! You are correct that the premise behind EI is that you can avoid any high enough overdose as to harm the fish by doing the weekly 50% water changes. But, Tom has always said that he really prefers to just start with the EI dosages, then gradually reduce them, one at a time over several weeks, until he sees some adverse effect on plants, then he goes back to the dosage that didn't show that effect. Then, do the same with another of the ferts. Etc.

A trap in that method is that as the plant mass builds up from the rapid growth this will cause, the plants need more nutrients. (This includes CO2, so you have to be sure to maintain good water circulation, so the drop checker will reflect something close to the amount of CO2 the plants see.) Trying to use just the dosage that doesn't cause adverse effects on the plants can leave you under dosing if you don't allow for the increased plant mass. Even for that case, if you are observing the plants carefully every day you should notice the effects from the gradual under dosing and be able to adjust the dosage back up. Frankly, I am too lazy or unobservant to try that, so I just use the EI dosages all the time.

Those of us dedicated to this hobby to the max will do continuous prunings to maintain a stable mass of plants in the tank, and that will eliminate problems with required dosages.
 

rich815

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Jun 26, 2008
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VaughnH;27131 said:
Ah! One more convert to EI! You are correct that the premise behind EI is that you can avoid any high enough overdose as to harm the fish by doing the weekly 50% water changes. But, Tom has always said that he really prefers to just start with the EI dosages, then gradually reduce them, one at a time over several weeks, until he sees some adverse effect on plants, then he goes back to the dosage that didn't show that effect. Then, do the same with another of the ferts. Etc.

A trap in that method is that as the plant mass builds up from the rapid growth this will cause, the plants need more nutrients. (This includes CO2, so you have to be sure to maintain good water circulation, so the drop checker will reflect something close to the amount of CO2 the plants see.) Trying to use just the dosage that doesn't cause adverse effects on the plants can leave you under dosing if you don't allow for the increased plant mass. Even for that case, if you are observing the plants carefully every day you should notice the effects from the gradual under dosing and be able to adjust the dosage back up. Frankly, I am too lazy or unobservant to try that, so I just use the EI dosages all the time.

Those of us dedicated to this hobby to the max will do continuous prunings to maintain a stable mass of plants in the tank, and that will eliminate problems with required dosages.


Yeah, thanks Hoppy! You know the advice one must filter through can get so frustrating! You have no idea how many people have either told me in person or in forums to stop dosing Phosphate since my fish bioload is giving me enough (based on the cheapo test kit) and that too much Phosphate will give me algae. I am getting such strong lush growth right now, particularly my Dwarf Val foreground, which is not as "Dwarf" as it used to be nor very good for the "fore" either it's doing so WELL, that the increase mass of plants is creating a few dead zones where little flow is getting, and THAT I think is what's causing me to get some BBA and GSA since the CO2 might not be getting those areas as well. Seems with a strong dosing regime and pressurized CO2 that my days of once/month pruning is now going to be once/week if I want to keep things neat and keep the water movement and flow consistent and good in all areas. And some are insisting that if I have GSA it's because I am low on Phosphate and i have no reason to doubt their word on that.

Some people told me when I was considering going from my 2 watt/gal, no CO2 (just Excel) tank to a stronger T5 HO lighting set-up and CO2 that I should be ready. The latter is like driving a high-end sports car: it's goes faster and requires more precision and attention to detail otherwise I may lose control. Well, I sure see what they meant. My whole planning of plant placement and pruning routine needs an complete new overhaul in my thinking now too.
 

VaughnH

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You might want to consider an aquascape that has a concentration of plant mass in the middle of the tank, with only very low growing plants around that. An advantage of this layout is that water circulation isn't blocked quite as easily by heavy plant growth. I have been trying that, but I find my light intensity is too high for the high mound in the middle - made of a mopani type wood "sculpture". So, I got BBA on the wood, then took a week vacation and the BBA is now in several places. The longer I play with this hobby the more convinced I become that "good" lighting is far less than "high" lighting.