Originally Posted by Christople
thank you for the info but I tested my pH and IT came up as around 7.6!!!!!!! wowowowowowowoowwow those test strips were way wrong. They said 6 ish
Test strips are not very accurate as you have found out. There are better test kits for KH, GH and PH, and really good hydrometers for measuring NaCl in water. Which I suggest that you get before thinking about adjusting water chemistry in your aquarium for any means.
I plan on slowly bringing it down to around 6.5 for the majority of my fish like that.
Your fish have been adapted to your aquarium for how long? There is a saying that if domesticated fish have been adapted to your water parameters and you are unsure of water chemistry sometimes it is best to leave what is not broken alone. Unless you are planning on breeding specific species. Personally I would just leave your water at 7.6 ph. As your fish have or are in the process of adapting to your aquarium.
How much ph down do I put for thirty 8 gallons
Personally I do not like any chemical use to lower ph as it can cause PH bounces in your water and I do not recommend this unless you are attempting to breed a species in their own tank. Or have the chemical knowledge and proper test kits to measure GH, KH and PH. (TDS meters)
There are better ways to lower the amount of mineral content in aquarium water. Some are expensive while others add tannins to the water. Tannin Information
All methods should be done slowly to prevent ph shock to the fish.
Another means is adding distilled water to your aquarium to lower ph down to neutral. This removes some mineral content slowly then once the tank is at neutral with no "gravel that can contain mineral content" then the tank is at neutral. This can be expensive for the cost of distilled water.
The other means is by using reverse osmosis water which is a filter process that takes out minerals and other impurities in the water see Reverse osmosis - Wikipedia, the free encyclopedia
Then specific things like Peat Moss can be used in the filtration of water to bring water below ph 7 which is the neutral point in the PH scale. I won't get into the methods for doing this part as it again takes proper test kits and knowledge to maintain this environment. It is easier generally to add specific minerals to alkaline water than to change alkaline water to that of water with specific acidic properties. Although again this process would also have to be done slowly for the inhabitants of your aquarium to adjust. There are products used such as Black Water Tonic that are used by some but again chemicals added have to monitored regularly.
As I stated I would not mess with the water chemistry in your aquarium unless you are taking on a challenge to breed a hard to breed species such as Discus