Changing substrate in large tank

yeliabkcin

Hi there

I have a large (300L) tank which at the moment is stocked with a Jack Dempsey, a Peacock Blue Cichlid, a Frontosa, a Pleco and some sort of catfish. The Substrate at the moment is a thin layer of robust red and black gravel, which doesn't look ideal - especially as these fish have taken a liking to moving it all around to make hills and bald spots. I want to change the substrate to washed sand but I'm worried that in doing so I will upset the balance of the tank's chemistry and need to cycle again. Does anyone have experience in changing substrate in a large tank like this, or have any tips/tricks to minimise disturbance? I have an alternate tank that I can use to temporarily house the fish while I do the change, but it is too small for them to live in for a whole cycling period if that becomes necessary.

Cheers

Nick

AbbeysDad

Hey Nick, welcome to TFK.

Lots of folks here have replaced substrates successfully. There are a couple of things you can do to minimize any beneficial bacteria upset. Since (I think) you don't currently have plants, you might add some floating plants that will help deal with ammonia as things settle out. You could also bag some of your existing gravel in media bags or nylon stocking material and leave in the tank for a week or two following the change. Since you're filter remains unchanged, a fair amount of biology remains there so with other measures, the transition should be smooth.

Note: I'm probably overstating the obvious, but be sure and rinse the new sand really well as lots of folks have issues with cloudy water following the change to sand as very fine, dust like sand particles can be a real pain.

AD

yeliabkcin

Thanks for your help. You are right about having no plants in the tank at the moment, so I will definitely try to get some for the period after the change. Any particular types you would recommend? How many plants do you think I should get?

Looking forward to washing all the sand (not). I have sand in one of my other tanks, and I think the washing job I did on that was good because I haven't had any cloudiness issues.

Again, thanks for your help

Nick

AbbeysDad

I have some Anacharis floating in my tank and it's doing really well, throwing new shoots. It's technically a stem plant, but does well planted or floating. There are others - have a look in the tropical fish profiles section (top of the main screen) under freshwater plants.

1077

+one,
I would also leave a fair amount of mulm in the bottom of the tank when I removed the old substrate.
This will help accelerate bacterial activity in new substrate, which might also prove beneficial to plant's by helping to breakdown organic's a bit quicker which would feed plant's.
Would toss a few trumpet snails in the tank as well to help sift,aerate the sand.
Only saying this is what I would do.