Backyard Aquaponics
A place to discuss aquaponics

Hi!

It has recently been suggested by a visitor to add sandblasting sand to the fish tank within the aquaponics system in order to prevent salt (from the water conditioner) from building up on the top grow media within the grow bed. I normally just rinse the top layer of the grow media to remove the salt that builds up from evaporation. Does anyone have experience with or thoughts on this?

Thanks,
Shannon

Hi Shannon, welcome to the forum.

My advice is don't do it! The person you spoke with probably thinks this will help with evaporation, and it will, but it's not a good idea. The sand would not stay on top and you'd still wind up with salt deposits. Lowering your water level would help with the deposits - they'd no longer be on the surface. You'd still get deposits and you'd see them when you pull plants - it's pretty tough to avoid. Shading the grow bed might help as well because this reduces evaporation. There may be some other things you can try but the grow beds do need oxygen.

I had a look at my system the other day after being away for a few days and found I was down to about 6 inches of water in my tank. The weekend prior I had pulled the discharge from my pump into a new location on my bed, but it was spraying every where and wetting the surface. Ended up evaporating more than half my water in a week (It was hot and windy). Filled up my tank (with unconditioned tap water), and modified the discharge to below the surface, and evaporation rates back to normal. Wet layer is about 1" below surface.

I'm with Scotty, keep the water below the surface of your GB, and don't add sand. If it is used sand it will have all sorts of contaminates in it.

I was leery about the suggestion and wanted to research it more. The system is nearly 2 years old and since I've been managing it, I've been rinsing the top layer of media about once a week, and the guy before me did something similar. I have extra media so I'll add that to 'lower' the water level.
Thanks for your thoughts.
Take care,
Shannon

Scotty, they said sand in the FT, not GB.

dont add the sand, its not needed.

have you checked your salt level? salt build up sounds like you must have a fair bit in there.

Yep, I can add blindness to my list, must be losing it Yavi. Thanks for the heads up.

To Shannon - my apologies for the error - FYI - the sand does not belong in the tank either. The best solution is probably just to lower the water level in the grow bed (or raise the media level). It's not a perfect solution but it will help.