I could use some advice about adjusting my current EI dosing. I have a 50 gallon tank with 2.6 wpg of PC lighting. The tank has been running for 6 or so years. I know my tap water is hard, pH stays around 7.2-7.3. Temp kept at 74 degrees, packed with lots of healthy fast growing plants, 8 Pelvicachromis taeniatus, 15 Cardinals (12 added 3 weeks ago), a bristle nose Ancistrus, 4 ottos and an adolphoi cory. Substrate is sand and I have two Eheim filters running on the tank a 2026 and an older Ecco 2233.

I started EI dosing the tank 4 months ago after neglecting the tank and developing a horrendous clado infestation. After manually cleaning the tank I started doing EI, Excel dosing and proper maintenance and the tank turned around beautifully. The clado never came back. Up to now virtually no algae except some negligible GSA that can easily be removed each week if I can find it to remove, minor enough that it is hard to see. Getting great plant growth too. I plan on adding pressurized CO2 but for a number of reasons this is not going to happen for a few months.

Using the standard EI dosing schedule, 3x a week macros, 3x a week micros, daily Excel with the standard Seachem recommended overdose after my weekly 50% water change. I started with the dosing suggestions for a 20-40 gallon tank since I am using Excel not gas, and tweaked a bit at 3 week intervals. Currently dosing the following

3/8 tsp KNO3 3x weekly
3/16 tsp KH2PO4 3x weekly (I upped this a bit because of the GSA)
1/4 tsp K2SO4 3x weekly (upped this a month ago as an experiment after reading EI ppm target ranges)
5 ml Flourish Comprehensive 3x weekly
random dosing of 5 ml Flourish Iron though I have pretty well stopped dosing iron.
Daily double dosing of Excel.

I am starting to get a bit of thread algae. The long thin non-branching single strands, pale green color to almost no color. I can easily pull it off and remove 6- 10 strands from around the tank every other day or so. I would like to make sure this doesn't develop into a problem. Since I can't add gas at this point I would welcome suggestions as to how to work with the tools I have and optimize dosing levels to stave this off. My guess is that I have hit a point where my plants are happily sucking up all the light and nutrients but slightly carbon starved. Realize I probably do not need the amount of Potassium I am adding but have never read about that causing algae problems. I was curious though if the extra Potassium drives consumption of one of the other macros causing it to get depleted quicker.

Thanks
Steve

Hi Steve,

Why would you stop dosing FE? What type of substrate do you have? I also have Excel tanks and dose TMG regularly(a source of FE)

Hi Chris
Sand substrate (plain old Monterey Bay Aquarium sand). I primarily stopped 3x a week FE dosing because I wasn't totally sure that it was necessary since there is some FE in Flourish Comprehensive and I wasn't seeing any obvious deficiencies in my plants. I had initial target ranges for EI dosing to follow and tweak but no real guidelines for FE dosing. I still add 5 ml about every week or so but am not certain it is needed.

Hi Steve,
Sorry about the late reply, out of town on business. Not sure what flourish comp has for FE. I do use TMG in my inert sub tanks for trace/Fe. Be careful holding back on macs or mics, a balance of these doesn't cause algae. Try wc 2x week and clean filters well. Also how long since sub has been deep cleaned?

Hi Chris

here is a link to a table that compares the nutrients found in Flourish Comprehensive, TMG and CSM&B.

Fertilizer Comparison

Haven't deep cleaned most of the substrate in a while, would have to uproot plants to do it but I do vacuum the surface of the substrate each week and deep clean the sections I can get to. For now I will continue to keep the tank and filters clean, have upped my Excel dosing slightly and have cut back just a bit on KNO3 to compensate for the increased fish waste from the recently added dozen Cardinals. I reduced the dose by about a 1/16th of a tsp starting with Saturdays water change and so far have not found any more thread algae. It was minimal anyway but my goal is to make sure I don't get a full blown infestation. The tank has been doing really well since I started EI so as long as I avoid making large drastic or continuous changes I feel confident that things will be alright. Will keep at the reduced KNO3 level for about 3 weeks and observe the tank carefully before trying anything else. All part of the learning process and I agree totally that the last thing I should do is stop adding ferts.

thanks
Steve