Brass vs Salt Water

I have a question about how brass reacts with salt water and the things that live in it.  I am currently fighting a problem of maintaining a balance between the amount of water being pumped into the tank and the amount leaving.  I am looking for a sliding gate valve because they are easier to fine tune than the ball valve I am currently using.  The problem is that I am having a hard time finding a PVC one.  Could a more readily available brass valve be safely used? 

We have a float valve in the sump to control the R/O water input but the problem comes when the return is less than the pump output and the sump starts to empty.  As the water in the sump goes down the float opens, R/O water enters and overfills the tank.  If I could match the return to the output then the float would work as intended.  The adjustment to make this match is just too fine for the ball valve currently in use. 

http://www.championlighting.com/e/env/0001KR9kJBDwxugSWA9f1c 5/Products/Plumbing/plumbing.html?link=/Products/Plumbing/va lve.html

They have PVC gate valves.

Brass would corrode quickly and it has Copper in it which would kill any inverts.

How is the water getting from the tank to the sump?  In tank overflow, or hang on the tank siphon box? 

Edited by Sarnack

Sarnack,

  Thanks for the link.  At least now I know someone make them.

The pump is 1200 gph.  Can't remember the make right of the top of my head.  We have a 225gal tank w/ a 55gal sump/refugium so it does a good job of moving the water.  It pulls away for the drains because I (currently) use ball valves to restrict the amount of water coming out of the drains. (helps reduce the gurgling noise and sets the water level where I want it)  

Thanks for the website.

Sarnack,

Forgot to say thanks for the info on copper in brass.  Something was nagging me about brass and I couldn't figure out what it was.  Our crabs and shrimps thank you also.

Why restrict the drain?  You might as well get the full use out of the pump!  Either open up on the drain valve, or Google for "durso standpipe"  or "stockman standpipe" to get an idea how they work.  They are a DIY drain silencer that will cost you less then $5 to make.  If you need more instruction just ask.  I've got two on my 125 right now and they are absolutely silent!  The pump definatly makes more noise then the drain.

The pump is not restricted (well, just slightly to stop it from making air bubles. thanks again marcus).  I will google the ideas you sent jfinch.  Can never now too much.  The drain is restricted to reduce the distance the water has to drop while going down the return.  If left wide open the returns have more volume than the pump.

Your standpipe plan is excellent Sarnack, but our overflows are literally 2-1" PVC pipes in the center of the tank (spaced at the 1/3 point of the tank) so it won't work for us.  The plan is to place the tank in a wall when we build our retirement home so we wanted to have 360 degree viewing options (since we don't know how it will sit in the house yet).  We pile live rock to hide the returns and no overflow to look at.

Thanks for all the inputs from everyone.  We are still newbies at this and I like hearing ideas and opinions! 

hmmm.  A duro would work just fine in their setup except it wouldn't be skimming the surface.  Unless a skimmer box is used.  This is the DIY forum, so if it were me I'd make a skimmer box that allowed the drain pipe to go right through the middle of the bottom and put a durso in the box.  But that's just me.  What's it doing right now?  Just an open pipe at the top?  How are snails and stuff kept from being sucked down?

This is the kind of durso that I'm talking about that could be used right in the middle of the tank.  The image on the left is the same as the one on the right only with the outside fitting/pipe slid down so you can see inside.  This could be made on your setup using 3" pipe for the outside.  As marcus says though, it might be a little bulky.  Water level would ride where the coralline ends at the top.

Marcus, here's a picture of the return from my two dursos from a Velocity T4 pump.  It's really not too bad.  Almost any sump would make short work of them.

 

I think I've reconsidered dursos for this particular application.  Durso's when first started or restarted (like after a power blink) have a tendancy to pull a full syphon right at first which sucks most of the water out of the overflow box before stablizing.  In a tank without an overflow box the durso might suck out water all the way down to the bottom of the outside pipe (3-6 inches depending).  That might be enough to overflow the sump.  So if you're not installing an overflow box of some sort, I'm not sure a durso would be the best choice.

Actually I did it all on my own... but the idea isn't really orginal, I've seen pictures/desriptions of the same thing elsewhere (stockman drain) and I'm sure he didn't get the idea from me.

(reminds me of when I was 5-6 yrs old and I thought I invented "standing on the swing and swinging" only to find out later that every kid in every neighborhood in town was doing the same thing )