Changing Gravel

[michael.qian]

Hi all

I'm converting my tank to a planted tank and would like dark colored gravel, black or brown, as I think it can show the color of the plant better.

Currently I have the mixed color gravel, white, yellow, orange and black.

Is this a big job? Anyone has any experience with this? Is it likely to cause ammonia spikes?

I'm thinking of changing at least 60% of my gravel, so the top layer will be the new dark gravel and I'll probably leave a thin layer of the old gravel on the bottom, this way I don't have to uproot the biggest Osiris plant in my tank.

Cheers for any advice.

[David R]

If you don't replace all of it then the old stuff will mix in with the new. It can cause an ammonia spike, that said I've done it several times with fish in tank and had no problems, just keep an eye on the parameters after. If possible use a big siphon to suck all the gravel out rather than stirring it up trying to scoop it out. Although if you've got lots of gravel in a small tank it might not work.

[michael.qian]

I would think that most of the bacteria is on the filter media?

I have a Fluval 405 (bit of a overkill for my sized tank), it's got plenty of media in it, would that be sufficient? Considering the amount of fish I have right now is fairly low.

[David R]

Losing the bacteria isn't as much of a problem as stirring up all the crap in the gravel, creating more waste than the filter can process. Especially with deep gravel that hasn't been well siphoned and has 'dead spots'. You could try to get it as clean as possible first by doing a few deep thorough gravel siphons in the weeks/days leading up to the change over.

With such a small tank it might just be easier to get a couple of big 60L plastic bins and transfer most of the water and the fish into there while you re-do the substrate.

[michael.qian]

Yup that's what I'm planning to do.

I recently cleaned various spots of the gravel, it should be fairly clean now.

Will also siphon the gravel just before I change it, to avoid stirring up lots of gunk.

[whetu]

I second David's suggestion that you change all of the gravel. I once tried to 'cover' my multi-coloured gravel with dark gravel, but the result was still a mix. Unfortunately the darker coloured gravel was slightly finer, so all the larger light-coloured pebbles worked their way back up to the surface. I ended up doing a total gravel change a few months later and wished I had done it that way to start with.

If you're going to focus on plants, I would suggest taking all the fish and gravel out (including the large sword) and starting with a layer of something like Dalton's aquatic mix under the gravel with some slow-release fert tabs in places where you intend to have large plants. Then put your new dark gravel on top.

When re-planting your sword you will find that you can trim the roots quite hard. Sit the trimmed plant on top of the Dalton's then cover the roots with gravel and maybe a larger stone or two until it gets re-established.

The possibility of an ammonia spike will depend on the bioload in your tank, your feeding habits and the health of your filter.

[PS did you know David R has some dark gravel for sale?]

[David R]

:lol: I was going to mention that but I though it was a bit coarse [the gravel].

[suphew]

Personally, I'd be moving the filter and fish etc to another tank (or even a bucket, rubbish bin, storage box etc) and completely stripping and rebuilding the tank. The end result will be far better plus it will be easier and faster then stuffing round trying to syphon the gravel out.

[supasi]

Personally, I'd be moving the filter and fish etc to another tank (or even a bucket, rubbish bin, storage box etc) and completely stripping and rebuilding the tank. The end result will be far better plus it will be easier and faster then stuffing round trying to syphon the gravel out.

Agreed. :lol: :lol:

[michael.qian]

How's this for a plan?

I don't want to have to restart my filter, as it's a bit of a hassle.

Anyway here's my plan

Total volume is about 120L.

1. In the weeks before the change, make sure my gravel is as clean as possible, vacuum during every water change.

2. Move ~ 80L of water into a holding tank, with fish and plants.

3. Add some more tap water into my main tank, siphon gravel again thoroughly (add water so there is enough to keep the filter intake in the water and keep filter running).

4. When gravel is siphoned, scoop out all the gravel, hopefully not too much dust as filter is already thoroughly siphoned, then put in new gravel.

5. Put everything back.

Any flaws in the plan?

Cheers

[lmsmith]

I didn't think fluvals were hard to start - I think you'd still be better off taking the filter out. It's SOOOO much easier to empty a tank with no water in it - cleaner too.

Don't forget about your heater - make sure it's turned off or in water somewhere so it doesn't burn out or explode.

[David R]

If you don't stop the filter you'll have to afterwards anyway because you're bound to stir up a heap of crap and it'll get clogged...