pH Advice

[kmon]

I have a fully cycled (0 ammonia, 0 nitrite, minimal nitrate) 20 gal tank with 8 platies, 8 neon tetras, 3 zebra danios, and a bushynose pleco. The only issue I have is with the city water supply being very soft and thus acidic. Measuring the KH and GH I get 17.9ppm for each (both turn to their end-colour after the first drop using AP inc test kits). The acidity reads somewhere down around 6.4. The lack of salts in the water doesn't surprise me as most of our water (in the Cayman Islands) comes from either RO seawater or rainwater. My question is should I leave things as is or should I get something like crushed coral to try and buffer the pH up to something more around 7?

 

[Fishyfanatic]

I would add crushed coral to the tank. The low hardness readings are a recipe for disaster.

 

[Elle2]

I have exactly the same problem- my tap water is 6.2. Someone suggested that I add baking soda which has worked quite well. I am not sure if it is meant to be a permanent solution but I added a small amount and it brought my pH to 7 and it has been stable for the last 4 days.

 

[DepotFish]

That ph is fine for the tetras, zebras, and pleco. The kh should be at 8 for that combo though. Maybe you could lose the platies and do a low ph community combo.

 

[Jchillin]

Considering that you are in the Cayman Islands, I would think that any fish you pick up locally will have already acclimated to those parameters. The only time it would be an issue is if you ordered fish from outside your area.

 

[kmon]

Considering that you are in the Cayman Islands, I would think that any fish you pick up locally will have already acclimated to those parameters. The only time it would be an issue is if you ordered fish from outside your area.

Well that's true, I hadn't thought about that. I doubt I would ever order fish from overseas (I'm pretty sure that Fedex is not exactly first-class for a fish). But is the tank still going to be subject to big pH shifts without anything to buffer?

 

[Andyvette]

Well that's true, I hadn't thought about that. I doubt I would ever order fish from overseas (I'm pretty sure that Fedex is not exactly first-class for a fish). But is the tank still going to be subject to big pH shifts without anything to buffer?

No.
Chillin hit it on the head. The only shifting will occur with a buffer. It is always better to have a stable pH then the "ideal" pH.