Reef nutrition

Drain or no drain

I’m planning out my next build and I’ve seen some custom tanks with a hole drilled low on the tank so that you can plumb it for a drain for easier water changes. I’ve always been weary of it though since it’s a possible point of failure. What do you guys think? If you have one do you use it? If you don’t would you risk it for the extra convenience?
 
IMO, no.

For me water changes is more about just getting rid of old water and putting new back in, it's also a time to siphon out detritus and the like which will accumulate in some spots. If you want to make an easy enough water change you can more safely just make a "U" shaped piece of PVC one end connected to a hose the other end whatever depth you want based on how much water you want gone, and simply hang it over the edge of the tank and start a siphon. Easy enough to do, will drain to the prescribed level, doesn't require you to put a hole in your tank for the sole purpose of emptying water to a particular level that you won't be able to ever change.
 
I used to have a nice water change setup. My drain pipe had a T junction and two valves. One valve went through a pipe, through a wall and into the gravel driveway (rural Sacramento area), the other valve went to the sump. I shut off the return pump, close the sump drain and open the outside drain. Then I pump new water from my mixing can into the display. Water goes doen the overflow and out the hose to the driveway.

It wasn't the most efficient method since some percentage of the new water is going to drain outside but it was super easy. Open and close two valves and push switches to turn pumps on and off.
 
I wouldn’t. Plenty of easy ways to do automated or facilitated water changes that don’t involve compromising the tank.
 
Ok, this reaffirms what I suspected. @sfsuphysics I like the idea of the fixed length of plumbing so that it will automatically stop at a repeatable depth. I’ll be able to set it to 1 barrel of new salt water.
 
When I do water changes, I take out water at the same rate I put new clean water back in. Biggest advantage is besides ATO and skimmer, I can leave everything else on, so the new water is getting heated, circulated through sump, etc. Also don’t have to deal with dropping water level either in return chamber of the sump or the display, with all the issues either can cause.

The main reason I think people don’t do this is because they don’t like the idea of “wasting” new water they put in and then take out as the water change goes on. But this really isn’t a major issue for regular size water changes, only for massive ones.

Ex:
Say you have a 100g tank, and you will do a 20% water change-

- If you take out 20g and then replace 20g, you’ve changed 20g.

- If you exchange 20g continuously, at the beginning you are exchanging 100% old water, at the end you are exchanging 80% old water and 20% new water. On average you are exchanging 90% old water and 10% new water, so over the course of the 20g water change you exchange 18g old water out.

So 2g new water “wasted” but with the huge advantages of maintenance of water level and acclimation of water continuously.

If you do smaller water changes, the efficiency is higher, for example with a 10% water change (10g) you waste 5%, or 0.5 gallon in this scenario.
 
When I do water changes, I take out water at the same rate I put new clean water back in. Biggest advantage is besides ATO and skimmer, I can leave everything else on, so the new water is getting heated, circulated through sump, etc. Also don’t have to deal with dropping water level either in return chamber of the sump or the display, with all the issues either can cause.

The main reason I think people don’t do this is because they don’t like the idea of “wasting” new water they put in and then take out as the water change goes on. But this really isn’t a major issue for regular size water changes, only for massive ones.

Ex:
Say you have a 100g tank, and you will do a 20% water change-

- If you take out 20g and then replace 20g, you’ve changed 20g.

- If you exchange 20g continuously, at the beginning you are exchanging 100% old water, at the end you are exchanging 80% old water and 20% new water. On average you are exchanging 90% old water and 10% new water, so over the course of the 20g water change you exchange 18g old water out.

So 2g new water “wasted” but with the huge advantages of maintenance of water level and acclimation of water continuously.

If you do smaller water changes, the efficiency is higher, for example with a 10% water change (10g) you waste 5%, or 0.5 gallon in this scenario.
That’s a really good point. That is actually precisely the thinking I had. Now that you put it that way I’m reconsidering that option.
 
My used 120g came with one side corner overflow removed, so they used that hole for drain like you said, with about some angled fittings and strainer high enough to stay on top of the sand. Haven't had any issues with leaks, and my stand is high enough for 20g brute on casters to drain into.

However, you get some stagnant water inside the drain hose that doesn't circulate, partly because they have about 2 feet of hose and they put the valve at the end of it, so might add a little water quality issue. Whenever I drain that first bit, stinks like butt. I think I could have solved it, which I was thinking of doing, but too lazy to do, is build in a closed loop with small pump to the smaller return hole next to it that I plugged up. Also should have put a valve right at the bulkhead so I can change out hoses or did my closed loop idea a lot easier. With closed loop, and a tee and valve for drainage.

Also, nearby green mushroom rock I had before was next to strainer, so now it's covered in green mushrooms. No real issues, and actually covers it up nicely for better aesthetics.

I wish I did have dual corner overflows though for better circulation and even return flow. But been like this since 2010, so all good.
 
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