[hoppycalif]

When you decide to use the EI method of dosing you are accepting as facts that excess concentrations of nitrates, phosphates, etc. will not do any harm to the plants or fish. The whole method is built around that, and is intended for those who do no testing of nutrient concentration in the tank.

When you do test for nitrates, for example, you need to just look at the results as being of minor interest, but no importance, or you have to carefully calibrate the test kit. That means making water solutions with known ppm of nitrate in them, and using the test kit to make sure it reads that ppm accurately. (Or, you can make your own calibration table of color vs ppm instead of using the manufacturers table.)

Plants consume nitrates. They consume more nitrates than anything else in the water except CO2. So, it is difficult to maintain enough nitrates in the water to keep the plants non-limited by nitrates. Cutting back on dosing nitrates would only be a good idea if you were changing water every other day, and the change water had a high nitrate level from the tap, a very unlikely thing.

I suspect your GSA problem on leaves of a stem plant are caused by the plant's growth being inhibited by too little nitrate, making the leaves susceptible to algae attack. Algae doesn't grow on healthy growing leaves.

 

[hoppycalif]

From Tom Barr's forum I know that some people with heavily planted tanks do increase the EI dosages, sometimes to double the recommended amounts. Tom once told me those dosages are intended to be enough for even heavy planted tanks. So, I'm not sure whether increasing the dosage is a good idea or not.

One thing I am sure of is that when the tank gets really full of plant mass like that it slows down the water circulation in the tank a great deal. And, that can cause some plants to be starved for CO2 if not for other nutrients. I have learned the hard way that as beautiful as I find a tank that is really heavily planted, I always end up regretting not doing more pruning, after BBA starts growing all over the tank. Your tank doesn't seem to be quite as stuffed as I have let mine get, so you probably still have time to figure out what to prune to keep it from growing too much.

I always dose twice the EI recommended amount of phosphate to help control GSA, and it does help a lot. And, as to slightly increasing the dosages - don't bother, because they are such a crude estimate of the plants needs to start with, a 20% increase or decrease would probably not even be noticed by the plants. If you do increase them, just double them. The weekly 50% water changes will protect you from building up way too much of any of the fertilizers.