Of course, strong acids are ions, but if you're starting with RO water to begin with, you don't need to add much acid, so the contribution to conductivity is negligible. If you started with a very high KH, you would need to add a lot of acid to neutralize it, driving up the conductivity even further. Starting with RODI, I'm able to keep the EC below 25 and the pH below 5.So the acid will raise tds ? Will it take water changes to remove the tds increase by acid ? My ec pen has a 500 and 700 choice but i think ec was around 8 (tds 26).
I'm not sure how you're calculating TDS, but with an EC of 8, TDS = 8 * 0.64 = 5.
The problem with "strong acids" is that they don't add any buffering, they disassociate fully, whereas "weak acids" don't and they have two disassociation constants. Personally I'd keep well away from both concentrated (conc.) acids and strong acids. Have a look at <"citric acid"> and <"All the leaves are brown">
Yes, I understand that strong acids do not buffer at low pH. However, the lower the pH, the less acid you need to neutralize the residual carbonate. The pH will always drift toward 5.5 (in my case) but the kinetics are such that, at least in my aquariums, I can keep it a range below 5 until the next water change (when I add more acid). The EC remains below 25.
Citric acid can work, but as Regani notes in that thread, it degrades over time, and he eventually shifted to mixing it with HCl. The advantage of the citric acid component is that it lowers conductivity further by complexing divalent cations. Is that necessary? In my case, no. I also don't know by how much it reduces.
It depends on the species. I've never kept a very low pH tank for an apisto species, but I've also never kept true blackwater apistos. I do maintain low pH tanks for wild caught Parosphromemus. The guidance is that the immune systems of these animals, through natural selection, have lost the ability to defend against pathogens that thrive at higher pH. So it's a prophylactic measure to prevent them from seeing those organisms. Is that necessary? I don't know for sure, but some very experienced (and academic) keepers strongly recommend it. Given the scarcity of these animals, I'm not going to experiment with it myself.So you are saying (i think) ignore ph and just be happy tds is 25 ec is 8 and it will all work out ?
I would determine what's actually needed for your species, based on the literature and breeding reports.
I've not seen a liquid fulvic acid that is low in pH. I believe its solubility in water is poor, so NaOH or KOH are added to keep it in solution. So, beneficial for some reasons, but ineffective for lowering pH.Have you ever considered Fulvic Acid, Darrel?