silverbeat

Hi everyone, I'm new to this forum but not to the hobby. I have a 55 gallon NPT that I set up last month, I didn't read carefully and covered my soil with about 4" of sand, got a huge hydrogen sulfide buildup. I removed most of the sand and poked at the substrate with a chopstick, releasing a lot of bubbles. I did a huge water change and my fish are fine now, all other parameters are normal-- nitrates barely detectable, and pH is 7.2 if that's relevant.

I don't necessarily like the sand and I was going to take it out and replace it but I don't know what to replace it with. I like the idea of leaving a thin layer in there and making little "paths" with smooth river stones, like these: http://69.89.31.209/~gottabem/robbus...picture-11.png the rocks would cover maybe 1/3 of the substrate alltogether. would that be alright? Any other suggestions for what I should use? I have featherfin synodontis and corys in the tank so anything that won't hurt their barbels.

Plants I have in the tank:
-watersprite
-wisteria
-onion plant
-dwarf hairgrass
-amazon sword
-moneywort
-tiger lotus [just a bulb and roots at the moment]
-also anubias, flame moss and java fern, not in the substrate
-planning to add a banana plant

Thanks very much!

NeonFlux

Yeah, those rock pebbles would do fine. Make sure to wash them well. Creative ideas haha. Welcome to APC, by the way.

mudboots

I recall some smooth substrates that come per size, sold at Dr.s Foster and Smith I think, but they are very pricey for a substrate cap. But if you feel like money is no issue, then you can certainly find some smooth material that is still smaller than the typical gravel sold at many chain stores.

Diana K

Look into materials available in the rock, soil and masonry yards near you. Bring home some samples and test to see if they will alter the pH, GH or KH of your water. Many will be chemically neutral, and most will be a lot cheaper than buying gravel at pet stores. You can probably find some fairly fine gravel that will look really nice and work well as an overall cap, and some fancier pebbles that you can create paths with.

Sophie and Mom

Could you please let me know how you will accomplish this? I'm in the same boat--I have a cap I'm not happy with, and want to replace it, but I don't want it to be a week-long government project!

Diana K

Doing a change of just the cap can be a bit tricky, but is possible with the fish and plants in the tank.
Sand can be siphoned out. You may have to try different sizes of tubing (Vinyl tubing available at hardware stores) to siphon the sand most efficiently. Air tubing might work. You might end up catching the water in the bucket and adding it back to the tank, perhaps several times. (You could also treat this like a water change)
Anyway, you will remove as much of the sand as you want. At some point you might decide that the little bit that remains can be mixed with the substrate, or just left there. You could certainly leave enough in one area to represent a path.
Wash the gravel before you add it to the tank.
Use a small container perhaps 1 cup volume and lower the gravel as close to the substrate as possible, and tip it out of the cup in small amounts so it does not pile up in the center of the plants. It is easier to arrange it near the plants by dumping it near then moving it closer with your hand or a tool like a flattened stick.
Another way to add the gravel is to use some stiff pipe like PVC. 3/4" might work best. Large enough to get the gravel into it, small enough to fit between plants. A piece of pipe that is a few inches (perhaps 6") longer than the water depth is best. You can angle it to guide the rock into awkward spots.

If the tank has been running a while there may be a significant amount of nitrifying bacteria living on the sand. Removing it can cause a spike in the ammonia. To reduce this chance you can add the right bacteria. Look for a product with Nitrospira species of bacteria. All other 'cycle in a bottle' products have the wrong species of bacteria.

Sophie and Mom

Great info, Diana. Thank you.

Sophie and Mom

With regard to the bacteria, would replacing the cap a little at the time be helpful in maintaining it?