I have normal aquatic sand as my subtrate, and a mixture of granite, red agate and pagoda stone for rocks. I have 2 other tanks and without intervention for me they are typically 8.2 ph, the same as my tap water.
I have some bicarbonate of soda, so I will add that tomorrow. Just how much? 1 tsp per 10 ltr? Dont want to get the amount wrong. Fish are a bit pale, so I assume it is the low ph affecting them. Everything else is perfect.
Julia
Now, TBH i just have gone off the idea of adding anything to my tank, so i wouldnt add BOS. Im not too well up on my rocks either, but i do have rainbow rock in my tank, it keeps my pH over 8... I dunno, its up to you, i think its worth the money to use coral sand in your tank (dependant on size, £ wise), but i understand that if you do have a BIG tank this is not always possible... Ill have a look about adding the BOS for you...
Ok, here goes, i got this from a pinned topic, so i am not the author!
"The ideal PH for mbuna is in the general region of 8.0, but they are very adaptable and can handle a fairly wide range. If your tap water falls between 7.5 and 8.5 you have good water, and are best off using it as-is, with no adjustments. More important is KH, which acts as a buffer and keeps the PH stable. A KH of 8 or more is most desirable.
If your water is not quite desirable for them then there are a few ways to bring it up to spec. Crushed coral can help, as can limestone and other mineral rich rocks. These can be used as substrate or decoration, and can also be placed in a filter. This method is great because more water is forced through the media then as a substrate, and it leaves you with free choice for substrate. Canisters are best for this because they hold more media then most types. The more finely crushed the coral is, the more effective it will be, but at the same time if it is crushed to a sand it will impede water flow.
Another option for an easy method is to use baking soda. If may sound strange, but it actually works very well and costs next to nothing. Baking soda will raise the PH to 8.2, and no further no matter how much you use. The more you use, the higher the KH will rise. The elements of baking soda do get used up, so it is important to check the KH weekly to make sure things are good, and add more if necessary. You also need to add more for the water that you replace at each water change. Even if it sounds a little complicated now, you will quickly get into the rhythm and these additions will become second nature.
You can also use store bought additives, but keep in mind many of them are unstable, and you would be no further ahead then using baking soda, and you’d be spending more money too.
Regardless of what additive, if any, that you choose to use, it is important to keep an eye on parameters regularly to make sure values are remaining stable. Test weekly and add more as you need to. In general it’s best to avoid all additives if you can. More often then not the water is suitable right out of the tap, and weekly water changes will keep it stable".
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I think the coral sand is worth it because as the author says the elements of the BOS do get used up. I think it would be a headache making sure your water was perfect & checking on it almost constantly worrying if the pH is down again, pH swings etc, etc...
BUT... Thats just my humble opinion...
