Coral sand and high GH

[shinerb]

Hi all

I've finished cycling my tank. Ammonia dosing to 2ppm and ammonia and nitrites down to zero for three days, so today I thought I'd do a final check of all the readings before getting some fish tomorrow. During cycling I was concerned about low KH and pH, so added some bicarb as a temporary fix. A week ago I mentioned this at my local aquarium shop and they suggested I buy a four quid bag of coral sand (which I've since found out is aragonite?), telling me I should 'just spread half the bag' over the substrate. Rashly, I did that without doing any research. Whenever I'd bothered checking the GH during the cycle it was about 10, but today (the first check since the sand) it was 20! I can only assume it's the sand that's caused it. My tap water GH is 4, so I could tackle it with water changes, but my understanding is that this stuff continues to release calcium and carbonate for ages. The other option is to remove as much of the stuff as possible, which would be a hell of a job as I've mixed it with the gravel. And if I did, would the low KH/unstable pH problem be likely to return? Any suggestions appreciated.

[Stephen]

I can only assume the local store thought you were setting up a marine tank or an African Rift lake tank.
Argonite is almost inert in a marine set up but raises the GH in a tropical set up, as you have found.

As you only have a 60L aquarium I would replace all the sand/substrate and set up again from stratch.
The filter should be fine as you have already cycled it. Just dose with Seachem Stability to replenish any lost beneficial bacteria and to help prevent "new tank syndrome".
Maybe choose a more natural looking sand as Coral sand is very light in colour, I use Unipac Samoa fine sand (as in image below)




All the best

[shinerb]

Could I not just keep it in check with weekly water changes?

[fr499y]

It will be more hassle to do that than to change it. Also, any bottom feeders will suffer from the courseness of coral sand. It will buffer the GH, KH and PH which is perfect if you plan to keep malawi's ( Rift lake cichlids ).

[Stephen]

Could I not just keep it in check with weekly water changes?

That will be very difficult.

It will be more hassle to do that than to change it. Also, any bottom feeders will suffer from the courseness of coral sand. It will buffer the GH, KH and PH which is perfect if you plan to keep malawi's ( Rift lake cichlids ).

I agree.

Also if you intend to have live plants then now is the time to get things sorted.
1L of Tropica plant substrate (£6.49 from Pro Shrimp) topped with 4-5kg of Unipac Samoa fine sand (£5.90 for 2 x 2kg bags from Pro Shrimp).
This will give 1cm depth of plant substrate topped with at least 2cm of sand , you'll want the sand deeper at the back so maybe 6L of sand (3 x 2kg bags = £8.85 or even 1 x 10kg bag = £13.45).
3 x 2kg of sand and 1L of Tropica plant substrate = £15.34 which is not a massive outlay.
If you correct the errors now (before adding fish) it will make fish keeping far easier for you and the fish will also thank you for it.

All the best

[shinerb]

I did two big water changes today and got the GH down to 8, but presumably it'll continue to rise. The tank's already heavily planted and the plants are thriving, and dealing with the nitrates to the point where I'd barely need to do a water change before adding fish. That's why it's so annoying. I've got a Tropica substrate topped with fine gravel, and the sand is mostly just there on the surface under the plants. So I'm planning on taking all the plants out and removing as much of the sand as I can, then replanting. If there was just a relatively small amount of sand left would its hardening effect be reduced?

[LookoutTrout]

I'd be tempted to pick as much out as I can by hand to see if it stops the big swings. A fair bit of work but so is the alternative.

[Stephen]

Despite my disability I re-vamped my big 550L aquarium in a few hours.
My 120L aquarium was also set up from scratch in a few hours.
I do tend to be quite organised and everything was ordered and delivered ready which makes the job far easier.
I usually pay the price afterwards (back pain and more) but it's worth it (in my eyes). I will often say on this forum "No pain, no gain".

Is the Coral sand just coral sand by name as a description of the colour or is it actually coral sand ?
I would imagine that the aragonite is the biggest problem.

[shinerb]

Yes, it was sold to me as 'coral sand', which I think *is* aragonite(?). I've taken out as much as I can and replanted, so I'll just have to wait and see what happens.