Yvan asked about peat:
... Do you just use some amount and look the results (just monitoring) or is there any quantity/gallon to use? ... composition of the peat ... So many types ... use peat even if your water if soft and "acid" enough for your fish but just in order to bring them some of those other dissolved elements ...?
I am new to this and wondered the same. Trial and error has indicated that:
The pelleted form appears more potent (quantity wise) than the loose. I have used and like the Fluval brand, although it is pricey ($10 US/500gram box). I have Sera pelleted ordered, but have not yet compared it. I have used Kent Blackwater Expert but prefer the peat because of the greater impact on the pH. My tap water is pH 7.5 and I dropped it to 5 with peat filtering for several days on a newly set up 29 gal. tank. I filtered using half a box (box = 500 grams) of the Fluval pellets in a HOT Magnum. I now filter on a 44 gallon heavy duty plastic trash can reservoir. You have to gauge the time the filter runs and test regularly to hit the target pH you want.
On a similar note, I am also noticing that other methods of pH adjustment may (negatively) impact conductivity. I purchased a Watercheck from Hanna Instruments (thanks for advice from the archives) and recorded 100 μS for tap water and a pH of 7.5. I added the recommended amount of Seachem Equilibrium and Seachem pH 6.5 and the conductivity jumped to 520 μS. I will be pursuing a method using peat to adjust pH, which seems to have little effect on conductivity.