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Dosing with PMDD vs. the EI plan of macros, then micros....(from SFBAAPS)

Discussion in 'Estimative Index' started by rich815, Jun 30, 2008.

  1. rich815

    rich815 Guru Class Expert

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    Hello all,

    Fairly new member here. I am re-posting a forum question I had over at the SFBAAPS website as I'm hoping for some advice and input from people here as well. Tom already replied to my first question, and I followed up with more info and asking for further advice. Anything anyone can add would be appreciated. Original posting here: sfbaaps

    and repeated below:

    *********************

    Me posting on 6/20:
    I bought some PMDD Pre-mix from Alan at the last open house. He told me a good plan was to dissolve it in water (proportions on the baggie instructions) and then dose it at 1 drop per gallon once a day. I understand that PMDD is 1 part each of the macros: Potassium Nitrate, Potassium Sulfate, Magnesium Sulfate; plus the micro-nutirient mix (CMD+Plantex). Seems simple enough. So I used an empty Kent bottle I had, mixed it appropriately and have been dosing my 72 gal one drop per gallon each day (about a capful).

    But now as I've researched a bit more and been reading of Barr's EI and various postings about it and also some discussion of PMDD I have found some people saying that for a higher light tank (I'm about 4+watts/gal now) that dosing following the EI system of individual macros every other day, and the micros on the in-between days of that, and some GH at water change, would be better and would allow better control (with the 50% water change each week) vs. the PMDD. Some even said (I think even Greg Watson) that PMDD is best for lower light tanks and not high light for the very reason of better control and the ability to tweak amounts of macros using the EI method of individual macro doses.

    But what is the problem of using PMDD each day as Alan has said to and then 50% water changes each week? Seems from Barr's EI article that "over-dosing" some is not too much of an issue as the big change weekly would flush it out. Over-dosing is better than under-dosing (and of course he goes into detail about how overdosing of macros does NOT create algae issues). So, other than perhaps wasting some money by adding more of some aspect of my macros but simply using PMDD instead of individual doses of the macros is there some issue I should be aware of?

    Also, related to this: My phosphate levels (based on my cheapo phosphate testing kit) is about 3+ right now. This is way down from 2 weeks ago when it was easily 5+. I've backed off hugely on my feeding (I was overfeeding in a big way it seems) and also brought down my fish load somewhat. My nitrates are about 10-20 now (also having been brought down from 40+ two weeks ago). Knowing this perhaps using PMDD and it's inclusion of phosphate macro dosing is too much phosphate? Or should I not worry about it since I'll be doing the big water changes.

    Tom replies on 6/20:
    You can add more PMDD+PO4 to account for higher light levels.
    Which is pretty much what folks in SFBAAPS started doing about the time it was formed. Some went lean, some went richer, clearly, with 4-6 w/gal, I had better success with richer levels, and if you where a little low on CO2 and had lean levels of say PO4, then adding lots of PO4 switched the limitation to CO2.

    But you can dissolve EI into a bottle for 3-4 weeks worth and keep the trace mix separate, then dose daily, see PMDD style dosing for EI:

    http://www.barrreport.com/estimative-index/3209-want-more-accuracy-want-daily-pmdd-style-ei-dosing.html

    If you do large water changes, you do not need to worry over testign and higher PO4 at all.

    Main thing is to not over dose too much(you have a massive range for NO3 and PO4 etc) and you should easily be able to target 10-30ppm without much issue. You can also taper off as well.

    BTW, you had best calibrate the test kit you are basing your entire dosing routine and premise upon:)
    If not, then you are guessing, which means the test kits are not really telling anything that is of much use.
    This is particularly true for NO3 and PO4.

    Regards,
    Tom Barr

    Me again today:
    Thanks for the reply Tom, and the link. I've spent the last 4-5 days since reading that entire thread and others on your site. Became a trial member there too. Great resource and I look forward to seeing you in August at the open house.

    So far I think things are in good shape. I now have two Hagen T5 HO lights over the tank with a total of 4 bulbs, each being 54W. The difference in the light reaching the bottom of the tank of just one of those (108W total) vs. my 4-bulb (144W total) CF fixture was significant. So now with 2 of those T5 fixtures although the total wattage is 208W I get the feeling the lumens is giving me the equivalent lighting of about 4-5 watts/gallon if I used CFs.

    So, after a week of dosings of the PMDD Pre-Mix from aquariumfertilizers.com (1 part each of Potassium Nitrate, Potassium Sulfate, Magnesium Sulfate and Plantex CSM+B) at 2 capfuls a day (10 ml, about 2 drops per gallon), keeping the CO2 nice and rich (both a drop checker and my KH/pH tests show me at 25-30ppm there) I'm seeing wonderful growth on practically everything: my myrio and cabomba are adding about 1-2 inches a day and are just gorgeous, my new e. tellunus red cuttings from Boun are growing out a nice red and adding a new leave every day or so, my tiger lillies are coming out with new growth that has a rich red depth to their heretofore green leaves and are also growing at a nice rate, my red ludwigia is adding the biggest and reddest leaves I've ever seen, and even my anubias, which grew really slowly for me before, all added a full nice green leaf this week, plus new roots are evident.

    I did yesterday see the slight evidence of some early threads of BBA on some older leaves and found a couple of small spots of BBA I must have missed when I did my full clean-out and rescaping. I cut those leaves off, scraped the glass and treated some surrounding leaves with some excel to play it safe. I also noticed however, some slight greenish spots developing on the front inside glass in one area that may have been the beginnings of either GSA or green slim algae. I'm hoping both these green spots and the BBA was just because of my recent new lighting, new dosings regime and still getting my CO2 injection and dispersement in more consistent order (I also changed a couple days ago from one of those Red Sea CO2 reactors -- Freshwater Planted Aquarium & Plant Care: Carbon Dioxide Reaction Chamber CO2 Reactor 500 --- to a "Bill Hirada special" tapped directly into my eheim's outflow line), plus it was water change time.

    In terms of my phosphates as mentioned I've cut back a lot on my feeding and have removed a few fish to get the fish bioload down. My Nutrifin Phosphate testing kit shows me at less than 2.5 now (more of a powder blue result rather than the definite blue or even deep, dark almost black-blue of earlier). You mention, Tom., calibrating the test kit. Not sure how I do that, I imagine against a more expensive and better test kit. Can you recommend a better Phosphate testing kit and source for one? Nonetheless, even assuming this one I have is not entirely accurate relatively speaking my Phosphates do appear to be going down(mostly I'm guessing from the fish bioload being less and the stronger uptake of nutrients from the plants in the stronger light). If I stick purely to the routine of PMDD Pre-Mix mentioned above I'm thinking I'm going to come up short on my Phosphates soon. It'd probably be a good idea to add a bit of that to the dosing regime, no? How much would you recommend I dose for this 72 gal (likely with about 60-65 gals of water actually) if I get the KH2PO4 from aquariumfertilizers.com along with my PMDD pre-mix? Maybe start with 1/8 tsp KH2P04 3x a week?

    Thanks again.

    ******************
     
  2. rich815

    rich815 Guru Class Expert

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    Just now discovered on my normally relaxing nightly tank watch that BBA seems to be making a comeback. Trimmed the leaves I found it on but it appears to be making it's small but definite comeback on the driftwood pieces too. The driftwood had been covered in the stuff earlier but I gave serious H2O2 bathes to both pieces which turned it all red, I left the pieces out to dry out about a week before my total rescaping 8 days ago. My plecos and ottos stripped the driftwood sparkling clean of all the dead red BBA but it seems to be coming again.

    I'm thinking it's likely because of my inconsistent CO2 this week and lack of PO4. Any other ideas? Thanks....
     
  3. Tom Barr

    Tom Barr Founder
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    You can see the Tank at AF in SF which has 4x54W lots of light.
    More than enough to grow any plant you wish.

    Lamotte and Hach, Merak all are pretty good, still, calibrating test kits is a must for folks wanting to know information about their water.

    A poster named LeftC has many threads that are simple and show how to make solutions for NO3 and PO4 easily with a 20$ scale and some DI water and small mls flask.

    Still, your CO2 reactor seems way too wimpy for this sized tank, try a CO2 mist method, DIY in line reactor, Venturi and add more mixing in your tank.

    Any of these will help.

    Basic tenant: You need lots of flow by the CO2.
    You can turn the CO2 down or up as needed if you have excellent mixing and the respond is far more stable this way.

    If you have little flow going through the CO2 reactor, then you will have issues.
    You need lots.

    The RS 500 is a wimpy thing.

    Regards,
    Tom Barr
     
  4. rich815

    rich815 Guru Class Expert

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    Thanks for the reply Tom. Yes, the RS 500 was the reactor I HAD before. Just switched it late last week to a PVC DIY model that is installed in-line of the outflow tube of my 2028 eheim (see attached photo, similar to that one but with a clear middle tube to see the bubbles). I've turned up the CO2 a bit, now at about 3 bps. Will stay on the trimming and excel spot treatment of the BBA and hope for the best. Overall the plants are sure taking off!

    A couple of plants though are acting strange. My pennywort, one of the best growers I had with my earlier 2w/gal and excel CO2 set-up, seems to have slowed and the leaves are turning white, but not deteriorating, just getting white. And the leaves on my Echinodorus martii, while seemingly growing better too, are also coming out white and a bit transluscent. Is this just because of my sudden higher lighting?

    co2reactor_848.jpg
     
  5. VaughnH

    VaughnH Lifetime Charter Member
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    With the good CO2 and the high light, you need to provide enough of the basic fertilizers so the plants don't run short at any time. Following the EI method would be a good approach. Don't go by what the test kits tell you, because even 2 or 3 times the amount of any of the fert doses used in EI will not harm anything, so just dose as directed and do weekly big water changes to reset the tank.
     
  6. rich815

    rich815 Guru Class Expert

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    Thanks for chiming in Vaughn. In reading past posts here your input is certainly appreciated and valued as well. As you see from what I said above I've been using a PMDD-based solution from aquariumfertilizers.com though I am thinking to switch over to a more traditional EI method once I can get my hands on the ferts. In the meantime I too suspected maybe with such light I was underdosing so as of today I've upped it to 3 capfuls per day of the PMDD solution I made (1/4 cup of the PMDD from AF in one liter of water).
     
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