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Seachem Black Sand

997 views 7 replies 4 participants last post by  Surf 
#1 ·
I'm starting up a new tank and am thinking of going the African Cichlid route. At first I wasn't, and I purchased a larger bag of the Black Sand - I cannot return as I have opened the package and gave it the rinse already.

I realize that there are specific substrate for cichlids such that they keep the water hardness high.

Question is can I make do with the Black Sand that I have, and just get some limestone rocks to keep the water hardness up, or should I maybe invest in Caribsea's African Cichlid substrate...which doesn't appear as black as Seachem's.

Thanks
 
#2 ·
Have you tested your PH, KH and GH? If you have a higher PH and GH and a stable KH there is no need for a buffering substrate or additives.

I would also take some water from tap, test it for PH and then let set for a couple days ( or use an air-stone to do this process within 24 hours) and then retest. Do you have PH drift?
 
#4 ·
With African cichlids I would use rock, not wood--- because, yes, you will get some lowering of pH from wood.



Have you had African cichlids before? If not, I would do some reading/study about proper pH, hardness, buffering and how people go about raising it, if needed. Your hardness is good, but I would recommend checking KH to make sure that it is high enough that it is keeping the GH at a stable level. Also, your pH of 7.2 seems low relative to your GH? Is your pH test current_ not expired?

I have kept a lot of soft water cichlids, but not Africans. Even though soft-water cichlids have some areas where their needs cross with that of others; they also have specific needs that are particular to their species. I would look at the specific African cichlids you are thinking about keeping to make sure their needs are compatible with others considering.
 
#6 ·
My concern is that I was planning to use driftwood in the tank, which might soften the water and lower the PH I believe?
Wood an release tannic acid into the water. that will lower PH and will react with KH reducing the KH (carbonate hardness) level. Tannic acid will react with calcium and magnesium carbonate and convert it into a salt Which will not register on the kH test. However that is a temporary effect. Once the wood runs out of acid it will have no effect on PH and KH. What is most important to you is your GH is a measure of calcium and magnesium levels in water. Tannic acid will not remove calcium and magnesium from the water and as a result will have no effect on GH.
 
#8 ·
However, you mentioned that the wood will run out of acid - is that even possible? I thought tannic acid is always present in the wood.
There is a fixed amount of tannic acid in the wood. When it is in the wood it will have no effect water chemistry. It has to be leached out of the wood have any effect. Once it is in the water it will be removed by weekly water changes. Also bacteria will break down the acid to CO2 which will eventually leave the tank. So tannic acid levels will fall, but it takes time. How long is impossible to figure out.

Perhaps if I put crushed coral or aragonite into a filter bag in my filter that might help with the hardness.
calcium and magnesium carbonate only dissolve in acidic water. So if the water PH is above 7 they will have no effect on PH, KH, or PH. If the water turns acidic they will dissolve pushing GH and KH up but the PH will not stay close to 7. So if your current hardness level is Ok for the fish you should be OK. But if you need to increase the GH further you need to use a mix of calcium / magnesium sulfate or Calcium / chloride. These can push the GH up to whatever value you want. The dissolve at any PH and will have no effect on PH.
 
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