Aeration & Water Quality

[DaveS]

I've recently bought a Fluval 190L corner aquarium and have some questions.
It comes with an external Fluval 205 filter.

Water Quality
I've used rain water collected from my water butt to 3/4 fill the tank and added some tap water to finish filling the tank.
Is it ok to use water butt water, I seem to remember reading that it can be better than tap water?
I've been measuring the PH and my tap water is about 7.4 and the rain water about 6.8. However after a few days the tank seems to settle at 7.4 which is more alkaline that I would like. I've added PH Up which corrects it initially but then it always seems to revert back. Could it be the gravel affecting the PH. The shop gave me the gravel as part of the deal.. all I know is that the make is Roman gravel.. I don't know if it has any properties that might change the PH.

Aeration
In my tank from a few years ago I would always have an air pump with an air stone going. This tank and arrangement I have now hasn't got that. The In and Out pipes go through the bottom of the tank. The Out from the pump is set so that it sends a couple of streams from the output pipe and creates a ripple on the surface, is that enough to oxygenate the water?

Thanks.

 

[Tolak]

What's the hardness of your tap water, tank water, & rain water? Posting these numbers will help. Also, what fish are you keeping that you need to lower the pH?

If you have surface motion you probably have enough aeration, though this might depend on the fish you are keeping.

 

[DaveS]

What's the hardness of your tap water, tank water, & rain water? Posting these numbers will help. Also, what fish are you keeping that you need to lower the pH?

If you have surface motion you probably have enough aeration, though this might depend on the fish you are keeping.

Tap water is KH 89.5 with a GH of 17.9 although I found the GH difficult to measure. I believe we live in an area that is soft / medium water but we do get lots of limescale.

In terms of the fish; at the moment I've 5 tiger barbs to help with the water cycling until I'm happy that things are stable. I'm testing the water daily at the moment.
I've been reading up to pick fish that like the same conditions'ish; so my ideal tank would be: Barbs, Tetras, Gouramis.
According to my book the all require acid-neutral soft water. Mine at the moment is alkaline-neutral.

 

[thegnu]

you've added pH up. dont you mean pH down. anyway it doesn't matter the fish you want to keep will do perfect in your mix of rainwater and tap water

 

[DaveS]

you've added pH up. dont you mean pH down.

Sorry I do... I keep getting confused. Thanks for the advice.

 

[Tolak]

I would use plain tap water without any attempts at adjusting the pH. Your water is fine for those fish. Your book that says that they "require" a certain water parameter is wrong, most fish acclimate to a wide variety of water parameters without any problem.

My gh is 197 & kh is 107 with a pH of 7.7. I breed a variety of nw cichlids in this water. Look in your book and see what angels & apistos "require" for water parameters.

Adjusting your pH and causing pH swings is bad for your fish, tap water is nearly impossible to adjust as far as pH is concerned. The only reliable way is to reconstitute ro water.