Join Date: Feb 2012
Location: South east asia
Sometimes there is a catch-22, impossible combination. As in some plants don't grow well within the parameters you are willing to tweak. (as in using CO2 or asking you to change the substrate) If so, the practical solution is to switch out the plants for stuff that grow well within the parameters you can control, that the tank provides. Sometimes pruning or moving plants from one spot to another could work; some plants require more flow, or light etc.
Another experiment you can do is drop your ferts slowly and see whether your hypothesis is correct; If dropping phosphates/potassium to lower levels doesn't increase the amount of GSA/pinholes, then perhaps the actual levels required aren't as high as we think. Especially for low tech tanks, there can be a lag effect between action and reaction, not to mention other variables that have changed in the time period that we don't/can't test for (flow?light?redox balance?oxygen?intra-species competition?substrate compaction or deterioration?), so doing some reverse testing is useful. Tanks are constantly evolving, living things. Anyway if you can confirm the cause and effect this way, then just apply it there-after with peace of mind, the process won't crash the tank.
I believe the values above come from the EI guide on application towards low tech tanks. Can you post pics of the suffering anubias/repens ? Its an interesting scenario because one is a slow growing species that take nutrients from the water, whereas the other is a rooted fast growing stem plant. If they're both not doing well, its probably a tank-wide parameter that is amiss.
47g Journal of sorts
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