Thanks James.
I will stick to the sphagmum moss peat as per your advice - not a problem at all now you have supplied me with a link to it
That is good to know that I can prevent\minimise my KH drop. Maybe a better plan is... once i have finished presoaking drain off all the water, and add fresh tap water. leave it for a day and see if the KH drops. If it does just repeat the soaking and testing process.
This is going off topic now, and is a lengthy question, but if you have time I'd appreciate your input again...
As I am running no water changes, if my plants need something I have to put it in the water. I currently dose the water column weekly with:
Monopotassium phosphate
potassium nitrate
AE trace mix
gypsum and epsom salts. (The calcium is a new addition to my regime, I never needed this when I was running EI. calcium and phosphate go in on a separate day to everything else)
I get a nagging feeling that something is still missing though. Two things spring to mind:
1/ Chloride (I had no idea plants needed this until reading your remineralising recipe).
2/ KH - mine is slowly but surely dropping and at some point (about 3 months at the current rate) will hit 0.
I am at a loss about what further to add, how much and how often. or indeed whether I am worrying about nothing
Would a sensible approach be to make up a 25l container of RO water with your remineralising recipe, and then use this to top up my tank with weekly (I only add 1 or 2 litres a week from evaporation losses, or 10 litres if I clean the filter that week).
Should I alter the recipe in anyway as this is top up only?
Should I make the concentration stronger so that it can remineralise the whole tank (160l) and not just the 2l I am adding.
(my first thought was to just dry dose Calcium Chloride and potassium bicarbonate\carbonate weekly)
(I want to use RO for topup and not tap, as I can then leave it sitting ready for use in a dark cupboard ready for use, tap I let sit for a day or two to get rid of CO2 in it which I find inconvenient)