Ok, updates. It's a bit of a dogs breakfast at the moment, barely got it plumbed yesterday, got a new bulkhead for the overflow and it ended up being to big! This is after I hacked to death the old one trying to get it off, only to find I had to get it back on again. My hands don't work very well now. Anyway, got it going, very cloudy. Electrical's are still not done, RO and auto top off still has to go in, MH 250w has to be hung, list goes on.
Here are the pic's
It is a little full ATM, should be running a little lower. Water moves from right to left, it runs down a 15mm pvc into a 50mm pvc running horizontal and drilled to distribute flow. Return is via 3500lph (have to calc head loss). It doesn't make noise, nothing. and the I keep having to check the display because I think it is not running.
I added the additional two (middle) sections to hold the sand in place, that was laborious, considering I had to drain, and dig out the sand.