I have been using PMDD and MKP for a few months now ever since I set up a pressurized CO2 tank. I went off of a rough stab from someone on how much to dose, but that was when my plants were very small. Since I started the CO2 and the ferts the plants have exploded in size. I have a lot of swords mainly due to the fact I have large fish (due to my prior planting days) and I know swords will stay rooted well with the big fish banging around in the tank. I was reading about dosing at the following link: http://www.thekrib.com/Plants/Fertilizer/pmdd-tim.html and it made think I may be dosing too much, but I am at a loss. One main reason I am starting to doubt myself is the BBA that is now being treated for the 3rd time since I have gone with the ferts. I do not want to keep treating BBA, I want it out of my life for good. I believe my CO2 is constant, but I do not know the ppm for the tank since I do not have the water people order to do the proper testing in the drop checker. Here is a picture of the tank so you can see how "heavily" or "non-heavily" the tank is planted: The plants have all grown pretty fast. I do see a handful of yellow tips on the swords, I am sure that means something... Below are some answer to questions people might ask... Right now I am currently dosing 25mL of PMDD and 4 mL of MKP. PMDD is mixed 1/4 cup of mix w/ 500mL of water. MKP is mixed with 3/4 tsp of MKP w/ 1 liter distilled water I am running 2 Eheim 2217 Canister Filters, 1 on each side of the tank. I have 2 power heads running. PH and Filters = 10x turn over per hour I have 145 watts of light, T5 - Nova Extreme. Lights are on 8 hours per day on a timer. CO2 is about 3dps, I raised it to about 5dps since the BBA came back. Ammonia = 0 FE = 0 (It always reads zero, I am starting to wonder about my test kit) Nitrates = 40 - And I just did a mega water change 3 days ago and it just now read 40!!! I do about a 30% water change every other week. I am starting to think I need to make that weekly. I have tried looking up the dosing calculator, but I just do not know how to use it for PMDD and MKP. I am just at a loss and I want to make sure I am doing this right. I apologize if this is starting to look like a duplicate thread from the BBA thread I started in the algae thread. I thought I should start one solely for dosing as I am starting to doubt my methods. Thanks for all your help, you guys are always awesome!!!