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Right phosphate level?

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  • Right phosphate level?


    I'm new to this forum and I like what I see in the posts.
    Perhaps someone can help me with a question:

    Aquarium Information:
    Tank 48x12x24, 90 Gallons
    Light: 4x54W T05 Powerchrome midday ~6000 Kelvin
    Substrate: Sachem Flourite 15lb
    Heating: 200W & Root Therm 400 85F
    Water: GH: 5.0 (85ppm), KH:3.0, (51ppm) NH4 =0, NO2=0, NO3 =0 , according Test kit, ph 6.6-6.8
    KH and GH values are in german hardness, the water is pretty soft
    Filter: Wet Filtration system with EHEIM sump pump, Bioballs etc.
    CO2: Yes
    Water change: weekly, about 30%

    History: The tank was started around Thanksgiving 2007. I ran it for about 3 weeks without any fish, then added 4 Plecos, a week later 13 Harelquin's and another week later 5 Rainbow, 2 Pearl Gurami's, 7 Chinese Algae eater and 3 Bamboo shrimps.

    At the beginning the color of the tank went greenish, so I thought the nutrients especially with the fluorite was causing a algae bloom. So I added a carbon filter without any success. Then I switched to a diatom and the water became pretty clear. However green algae and hair algae started to develop.
    The Tiger Lotus exploded and showed a wonderful red color. The rotala's, myrophillum, cabomba and Ludwiga's grew well too, The echinodorus bleheri and the vallisneria didn't want to grow at all.

    Now the vallisneria take off but the Tiger Lotus, the cabomba and the Myrophillum came to a halt.

    Since about a week I noticed that blue-green cyanobacteria are starting to develop.

    So I was wondering if my phosphate levels are too high.

    Does anyone have a recommendation of a good PO4 test and what levels should not be exceeded.
    I already checked the city water report but there is no indication.

    Any help or advics is highly appreciated.



  • #2
    You didn't mention fertilizing. But, you did mention that your nitrates were zero. So, I assume you are not fertilizing at all, and your description of your problems suggests that too. May I suggest that you spend an hour or so reading something like Rex's Guide to Planted Tanks, which gives a good basic understanding of what it takes to grow aquatic plants. Then, many of the questions you have will be answered.


    • #3
      Phospate level

      Originally posted by VaughnH View Post
      You didn't mention fertilizing. But, you did mention that your nitrates were zero. So, I assume you are not fertilizing at all, and your description of your problems suggests that too. May I suggest that you spend an hour or so reading something like Rex's Guide to Planted Tanks, which gives a good basic understanding of what it takes to grow aquatic plants. Then, many of the questions you have will be answered.
      Hi Vaughn,
      Thanks for the link. Based on what I read it seems I need to increase my hardness.
      I will add some CASO4, KNO3 and K2SO4 based on the dosing recommendation from Rex and see what happens.
      In terms of the ferts I only used some fluid potassium from Seachem.

      What I forgot to mention is the driftwood. When I make a water change the driftwood smells rotten. I don't think the driftwood is a good one since I boiled it twice and the boiling water was very red. The green algae are mostly and heavily located on the driftwood

      So I might want to replace that too. Any recommendation where to buy good wood?
      Again Thx for the good read.



      • #4
        Plants of all kinds need NPK, which is why terrestrial fertilizer always shows the amounts of each right on the front of the bag - 10-10-10, for example. Aquatic plants have that same need. So we dose nitrates for nitrogen, phosphates for phosphorous, and (usually) potassium nitrate for potassium. Then, plants need an array of micronutrients, like iron, boron, sulfer, etc., so we dose a trace element mix. With more than low light intensity, which only drives the plants to grow very slowly, we can't grow aquatic plants successfully without providing NPK and traces. If you read in the forum here about Estimative Index dosing you will see that we dose potassium nitrate (KNO3), KH2PO4, and either CSM+B or another trace element mix. Your plants are being driven to grow fast by the amount of light you are using, so you have to provide those nutrients, above all else. Then you need to be sure you are providing enough CO2 to supply the plants need for carbon, which is the main element plant tissue contains. A drop checker is a good way to see if you have enough CO2 in the water.

        You can use wood you pick up on a walk thru the woods, if you clean it well first.


        • #5
          Wolfgang, where are you located also?

          Tom Barr


          • #6
            well based on a KH of 3 and a ph of 6.6 I believe my CO2 level is in a good range.
            According to the tables the optimal ph for this harness should be between 6.4-6.8.
            Based on the fact that my Nitrate = 0 I think I need to provide some source of nitrogen as you recommended.
            In addition I will use some CASO4 and K2SO4 to increase my GH.
            Some chelated Iron solution should help the Tiger Lotus to come back with a brighter red.



            • #7
              In a small town in New England about 35 miles North of Boston.
              So if anyone has cooling problems we got the snow. ;-)


              • #8
                That's pretty close to the Boston aquatic plant group, they have a good group of folks.

                things to get:

                Trace mix ( Tropica is great for a trace mix)
                CaSO4, and Epsom salt, (MgSO4).

                I'd add the following to a tank with that light:

                KNO3: 1/2 tsp 3x a week
                KH2PO4: 1/8 tsp 3x a week
                Traces, Tropica: 15mls 3x a week
                CaSO4, MgSO4: after weekly water change(50%): 1 tsp of each.

                That's it.
                Do that, add CO2 to about 30ppm for the entire day light cycle, then that's about it, clean filters, other general mainteance.

                Then go to a club meeting once or twice for the plant folks.
                They do not bite

                Tom Barr


                • #9
                  Well, I assume you refer to the New England Aquatic plant Society.
                  Started to read about them.

                  Thanks for the tips with the dosing. I already ordered most of what you recommended except the KH2PO4 and the MGSO4.

                  Since this weekend I add 5ml of The Tropica mix on a daily basis but I haven't received the shipment for the chemicals (KNO3 etc.) I already noticed that the plants are starting to bubble and the algae are slowing down in growth.

                  Keep you posted on the progress.

                  Thanks and regards


                  I'm quite excited and will follow your recommendations for the dosing


                  • #10
                    You need to add PO4, via the K2PO4.
                    MgSO4, Epsom salt, you can get that at at drug store.
                    You need to add the PO4, it is no different than adding NO3, or K+.

                    I think many have the assumption, perhaps coming from Reefs etc that PO4 is bad, it's not and I've been adding it, and telling folks the myths have been wrong concerning planted tanks.

                    That was 15 years ago.
                    Today, most everyone on line doses PO4 that also doses KNO3 etc.

                    Algae are not limited via PO4, they never where.
                    Additionally, where high plant biomass is present, it's not an issue either, there's no correlation when there's a lot of plants in a natural system between algae or plant dominance.

                    Tom Barr


                    • #11
                      I followed your recommendation for about a week except I didn't add the KH2PO4.
                      After 2 days I noticed an increase in green algae. So now I have removed my 2 driftwood locks, which smelled bad when I took them out.
                      When I measured my NO3 concentration after 3 days of the first dosing it still showed 0 on the test kit so it seems my plant absorb it really fast.
                      In addition I have ordered now a PO4 test to see what those show.
                      My water is as cloudy and green as it possibly could be. I did 2 x a 50% water change and have added since only some trace elements, CASO4, MGSO4 and some iron mix. The hair algae have slowed down, pH stable between6.4-6.6
                      In addition I ordered a Diatom filter to get rid of the algae.
                      Any other recommendations would be highly appreciated.




                      • #12
                        Wolfgang, that is like saying I ate balanced meals for two weeks, except I didn't eat any vegetables. You need to decide whether you want to fertilize by trying to use test kits to tell you what to add, in which case you absolutely must calibrate the test kits, or if you are willing to use a dosing system like EI, which doesn't require testing, but which requires dosing all of the nutrients the plants need. Right now you are trying to design your own system on the fly, and that just doesn't work.