RO units

[Micky V]

Hi Guys, due to my high KH/GH levels (source water issue) I have been looking into RO units.
Is it possible to buy a small portable unit & connect it to a submersible pump to create a loop that takes water from my tank & puts it back in with lower hardness.
Think most units need 3bar to run but I'm unsure if small pumps can generate this.

I have a 190ltr corner tank stocked with:
12 Neons
1 Mollie
4 Danios
2 Rainbows
2 Bristle nosed
2 Dwarf Gourami
5 Nerite Snails
Tank is 6 weeks old now & last set of tests (drops) were:
Nitrite 0
Nitrate 8
Ammonia 0
PH 7.4
GH 17
KH 11
The 2 BNC's are under the Courgette. (1 black 1 Albino)

[dinofred1]

how would you get rid of the waste.

[Mito]

I think you'd be better mixing RO water rather than circulating it. It could block up the membrane. I imagine it's possible but there's very little control over the hardness in the aquarium.

[plankton]

The molly won't like it if it gets softer, hard water is good for them, and the rainbows may be similar. The snails will do better in the harder water as well.
Just a heads-up........maybe think about slowly bring the hardness down (by mixing the RO with tap) after the molly and rainbows have passed in a few years time? Not ideal for the other fish of course.....
RO units take everything out, so you would actually kill all the fish just using RO water.....

[Micky V]

Thanks Guys, I suppose as the fish seem to be all doing well it would be best to leave as is.
As it is over 30 years since I last had fish I have been reading as much info as possible & as a result, trying to get things perfect.
Apart from PH & Ammonia I don't remember worrying about all these other levels then, in fact, not sure those tests were available.
Perhaps I shall change my top Fluval 206 filter (Carbon) for some Peat pellets but I'm not keen on slightly coloured water.

[Micky V]

I have decided, after my last hardness test (GH17, KH13) to get a RO unit. My thoughts are to add 20ltrs of RO when doing my monthly 25% (50ltrs) water changes.
Hopefully this will eventually drop hardness to high single figures.
What do you think?

[plankton]

You can't do large changes straight away.
You need to build it up to 20l out of 50l, try starting at 5l and build up to 20l over 4-6 months.