Substrate clumping
 

What causes this and how to stop it?
Thanks

Usually this is a sign of Calcium carbonate forming in the substrate sticking everything together. I had this in my old tank once. Not sure how to prevent it, my tank has no sand so i don't have to worry about it! :mrgreen:

Not a good thing more flow will help and something to stir it up a bit.
How deep is your sand anything less than three inches is useless especially if it is larger grains.

Useless in what context?

I guess I should load it up with SPS and absorb some of the Calcium, at lease that's what i can tell my wife :)

only about 1-1.5" in DT but there is 4" in refugium. There is lots of circulation. 2X tunze 6055 turned right up, and the 350gph return and about 100gph return from the refuigium The tank is only 50g :)

For NO3 reduction you need a min of 3" anything less will just turn into a nutrient sink.

I'll start a different thread on depth later on :)

I take it you don't agree. :biggrin:

Well, yes and no. Kinda. The thing is, I don't think you need sand at all, and if you use it, is 2 inches bad where 4 inches is good? If so, why? If not, why not? Don't worry, we'll get our own thread going :)