Originally Posted by Knifegill
Now we're moving in the right direction. Here is the picture I want to attain:
My aquarium (for softwater species) is held at a low pH and hardness, but buffered ever-so-slightly to prevent it from falling to pH levels below 4.0. Every week, when I do my 50% water change, I add a tiny amount of pre-dissolved buffering agent to my new water during the change process. This way, even though the gas levels go through a swing, hardness stays the same and is not so far from my tap level that a small error in dosing the buffer causes trouble.
The above scenario seems preferable to my current scenario of hodge-podge amounts of crushed coral that are unpredictable in their abilities to buffer water moment by moment, and seem to give out very suddenly with little warning.
So, powdered chicken eggshells and epsom salt, right? Will 1 to 1 work or should I have more of one than the other? How much per 5 gallons to raise the GH to about 3?
On the last thing first, I have no experience with egg shells. Personally, I would not put these in the tank, they are biological in origin. I may be off, I've no idea what else is in them. Just wouldn't do it. Plus it is an unknown as for calcium.
Epsom salt works, i've used it myself, it is magnesium sulphate (just be sure there is nothing else in it, just pure ms). It adds magnesium, and a little goes a long way. Last time I used it, I dissolved 1 level teaspoon in water and it raised the hardness in a 90g tank by 1 dGH. In total I used 8 teaspoonsful, and the GH was 7-8 for the week. The following water change (50%) I added only 1 tsp and the GH was 6.
In the 115g I used Seachem's Equilibrium. From an initial GH of 2, using 3 tablespoons (dissolved in water) raised it to 5 dGH and that tested the same every day for the week. Following week after 50% water change I added 1 tablespoon, and GH remained 4 for the week.
Now, to the side effects. Nothing seemed wrong in the 115g, but in the 90g I nearly decimated my plants. The swords immediately got holes in their leaves, and i subsequently learned that an excess of magnesium causes an iron deficiency, in that the plant shuts down assimilation of iron. It took months to save the plants. I gave up buffering water.
I would use coral for calcium and Epsom salt for magnesium, but carefully if you really want to do this. Or a preparation like Equilibrium which obviously seems to work without detriments, though costly long-term.
Dolomite in the filter will achieve all this much easier. Years ago I used about half a cup in the filter on the 115g and 90g and it kept the ph at a steady 6.4-6.5 (without it fell to 5). No idea of GH then as i did not have a test kit. But dolomite adds calcium and magnesium, and a little lasts for months if not years. I checked pH randomly (maybe every 3 months) and when it was beginning to lower, replaced the dolomite. This worked for a decade.