600gal (96x48x30)

[asnatlas]

I am debating on putting a 1.5" sched 80 BH (2.5" hole) on the back of the tank in the overflow area for a drain line to feed the BK400...

I wanted to get some ideas on where the best place might be to drill it if I were to put one on... The overflow is 16" wide and I have it lined up with the 2 studs seen in the pic...

 

[NexDog]

Why not just tee off the drain to the skimmer?

 

[asnatlas]

<a href=showthread.php?s=&postid=6722472#post6722472 target=_blank>Originally posted</a> by NexDog
Why not just tee off the drain to the skimmer?

That is what I was thinking at first but people posted that it may not work and what if this and what if that and it would work if you did this and if you did that... Just seems easier/better to drill an extra hole to feed the skimmer...

 

[jnarowe]

I went with a dedicated 1-1/2" BH for my skimmer primarily to add through-put and maintain it when I take the skimmer off-line. Remember that you need to move a fair amount of water through the skimmer so a "T" may not be enough flow.

My external overflow only holds about 3" of water when running and my BH is through the bottom. It draws from the surface of the overflow water though. It would be nice if you could figure out a way to draw near or at the surface too. I would think that would increase the likelyhood of getting more contaminants out through the skimmer like small floating particles.

 

[NexDog]

Why wouldn't it work?

On my system I've decided to feed both drains into the Deltec and choke off the pump until I get the desired water level. Will optimize skimming performance and elimate the need for a pump.

 

[jnarowe]

I didn't say anything won't work, just trying to suggest what I think is optimal. My entire system runs off one Sequence pump. That is all the flow I want going through my sump, but I do not like the idea of "choking" a pump. What I do is have a "T" just above the pump outflow with a valve and a 1-1/2" line going back to the sump. What this does is enables me to fine tune the flow and return just enough water to the sump to get everything dialed in quite easily. This is a very common way to do it and creates zero back pressure.

I also intalled just after the "T" a clear flip style check valve so I can visually see exactly what is happening to the flow. The valve also makes priming the pump very quick. Just open it wide and the pump immediately primes.

 

[tomasz]

Shawn what I did on mine is I did split one drain into two outlets on e goes to sump the second runs thru UV lights and then to sump. I did instal 2 ball valves on the drain and it works like a charm. I can adjust the flow any wat I want or I can shut off one side and have the water flow thru the other side. If I was you I would be more concern with havine only one drain for the whole tank. If it was me I would install second one for emergency only, if the water gets to high in the tank the second overflow would pick it up. Once you fire up the tank you know what I'm talking about.

 

[jnarowe]

And really, I feel that I need more than one just in case one gets clogged with something. Imagine moving that much water and while you are asleep a fish or macro-algae clog a the return even just a little bit. Disaster! I try to think of all the "what ifs" and being able to have significantly more drain capacity than needed is a big plus. That way you could literally shut one side down to say brush out the return line or maybe remove something stuck inside.

 

[AcroSteve]

All other issues aside, a 2nd drain from the overflow will come in very handy.

 

[Travis]

Redundancy, redundancy, redundancy.

 

[asnatlas]

/sigh

Ok, maybe I need to look into two new holes... If I do a 1.5" (reduced down to a 1") to feed the skimmer, and another 1.5" that would be higher then the main 2" drain (durso) that would be an emergency backup if the main 2" got blocked, would that higher emergency 1.5" handle getting the water back to the sump ?? I am only running a Seq Dart with 5ft of head...

 

[tomasz]

<a href=showthread.php?s=&postid=6725220#post6725220 target=_blank>Originally posted</a> by asnatlas
/sigh

Ok, maybe I need to look into two new holes... If I do a 1.5" (reduced down to a 1") to feed the skimmer, and another 1.5" that would be higher then the main 2" drain (durso) that would be an emergency backup if the main 2" got blocked, would that higher emergency 1.5" handle getting the water back to the sump ?? I am only running a Seq Dart with 5ft of head...

Shawn If you going to have one drain fot the skimmer and second 2" drain for the sump you will have to reduce the second drain by a lot. I have one 2" drain on my tank with dart pump and that drain is reduced in half by a ball valve. If I was you I woud take the 2" put a ball valve under the drain next split it with a T and put a ball valves on each end for flow adjustment. This is what I did on my tank and it works great. As of your emergency I would put one 2" hole higher then the first one. I would not go smaller then the 2".

 

[Travis]

Yes, an additional 1.5" drain for backup would be fine. There is the slightest chance that something could end up restricting your 2" main drain some time but it's not like there could be anything that is going to restrict it completely. The 1.5" will easily pick up the slack.

The rule of thumb with overflow drains is never to put ball valves on them. When you put ball valves on your drain lines, you are restricting the flow to the point where it matches the flow from your return pump. All it takes is one snail to go down the pipe and get stuck where the ball valve opening is and it will be enough extra restriction that the tank will start overflowing. It is necessary to put a valve on the skimmer line but I would never put one on regular drains. If any must put ball valves on a drain, they should have a backup drain installed without a ball valve that can handle all of the flow should one of the other drains get restricted. This is coming from someone who had a tank crash because my drain line got restricted, the tank overflowed, and all of the water was replaced with kalkwasser via the auto-top off.

 

[NexDog]

Why would it overflow? The return pump would pump all the water out the return section of your pump and shouldn't be enough to overflow a large tank. Just put a solenoid above the above bulkhead to shut off the return pump if the water level gets that far and you save the pump.

Every system is different but on my system the main reason to get the water to the sump is to get it to the skimmer. Sure there's a fuge down there and a grow-out section but all that is fine on around 800gph which the skimmer needs to function correctly.

 

[tomasz]

<a href=showthread.php?s=&postid=6727436#post6727436 target=_blank>Originally posted</a> by Travis

The rule of thumb with overflow drains is never to put ball valves on them. When you put ball valves on your drain lines, you are restricting the flow to the point where it matches the flow from your return pump. All it takes is one snail to go down the pipe and get stuck where the ball valve opening is and it will be enough extra restriction that the tank will start overflowing. It is necessary to put a valve on the skimmer line but I would never put one on regular drains. If any must put ball valves on a drain, they should have a backup drain installed without a ball valve that can handle all of the flow should one of the other drains get restricted. This is coming from someone who had a tank crash because my drain line got restricted, the tank overflowed, and all of the water was replaced with kalkwasser via the auto-top off.

Travis I'm not sure what size was your overflow, but mineis 2" just like Shawns and I tried every posible combination before I put a valve on mine. I reduce mine to 1", 1.25" and 1.75" dursos and nothing worked. I did use 2" durso with reduced pipe size after the bulkhead and it woudn't work either. After I did the ball valve with some adjustments I'm happy. Also the ball valve gave a control over micro bubles which is a plus. If he goes with emerganct bulkhead then there is nothing to worry about, right?

 

[nickb]

<a href=showthread.php?s=&postid=6729028#post6729028 target=_blank>Originally posted</a> by tomasz
I did use 2" durso with reduced pipe size after the bulkhead and it woudn't work either.

I'm confused. What 'wouldn't work'?

The flow through an unrestricted drain is higher than through one with a partially closed ball value, so the issue can't be flow rates. Micro-bubbles can be controlled at the sump level with baffles and perhaps by reducing flow with a ball value on the return pump or by raising the level of water in the return section. I can't see anything which you would gain by putting a ball value on the drain. but, I can see lots of potential problems. Am I missing something?

 

[tomasz]

<a href=showthread.php?s=&postid=6729097#post6729097 target=_blank>Originally posted</a> by nickb
I'm confused. What 'wouldn't work'?

The flow through an unrestricted drain is higher than through one with a partially closed ball value, so the issue can't be flow rates. Micro-bubbles can be controlled at the sump level with baffles and perhaps by reducing flow with a ball value on the return pump or by raising the level of water in the return section. I can't see anything which you would gain by putting a ball value on the drain. but, I can see lots of potential problems. Am I missing something?

Nick I have no idea why it would not work? The only think is when you are dealing with 2" bulkhead and then reducing it to 1",1.25" or 1.5" that is a drastic change in size, the flow was either too fast or too slow with not much adjustment thru the air hole.So I have no idea why it did not work, but I know it took me over one month to find the solution that I liked and what I have right now works like charm . If you would have 2" durso with no reduction it will suck the water in no time.

What are the lots of potential problems you see with the ball valves .Am I missing something?

 

[nickb]

Maybe I missed an earlier posting, but what is the problem which this is addressing? Why are you reducing the size of the drain? A 2" drain and a 1.5" drain will suck water at the same rate, as determined by the flow rate of the return pump. And if you are dumping the water directly into the sump, I can't see any reason to reduce the size of the drain.

Problems with a ball value have already been mentioned: getting blocked by snails, algae, etc. The valve will give sharp edges for things to attach to.

 

[tomasz]

<a href=showthread.php?s=&postid=6729342#post6729342 target=_blank>Originally posted</a> by nickb
Maybe I missed an earlier posting, but what is the problem which this is addressing? Why are you reducing the size of the drain? A 2" drain and a 1.5" drain will suck water at the same rate, as determined by the flow rate of the return pump. And if you are dumping the water directly into the sump, I can't see any reason to reduce the size of the drain.

Problems with a ball value have already been mentioned: getting blocked by snails, algae, etc. The valve will give sharp edges for things to attach to.

Nick if you going to leave the pipes(2" and1.5") wide open the water is sucked faster then the pump can pump, so if you dont restrit you are left with ton of noises and big bubles on top of small bubles. As of to alge glgae grow in the pipes I don't think it can happen becuce there is no light source (maybe I'm wrong). So the only think anything
can happen is if something can fall in it.

 

[starpolyp]

tomasz-in a drain situation, exactly how is water "sucked" faster than a pump can pump? I dont understand this concept at all. water isnt sucked out of a drain, it just flows through.

asnatias-

It is better to have the drain line full size and with no valves.
The valves not only restrict water flow, they restrict the natural flow of air that exists in drains. in a drain, not only is water flowing through, but there is also air, and that air cannot be trapped in certain areas of the drain line or else you can get nasty air and sucking sounds, and possible air lock in a worst case senario. If you put a valve on the drain and block it off slightly eliminating the air and restricting water flow, what you have is a syphon and you dont want a syphon to drain your tank.

Algae may not grow in the pipe, but you can have many other types of things growing in there. like tube worms (soft and hard) of different sizes, diatoms, and bacteria.

In this situation in which you want a drain to feed your skimmer (which i donnot prefer btw) , you want to have a drain for the skimmer lower in the prefilter box, and two drains to the sump that are slightly higher in the skimmer box than the skimmer drain line.

as usual, words are hard to explain situations like this sometimes, so let me know if any of this makes no sense.

i am seeing some odd advice (some good too) going around in this thread regarding plumbing, be careful what you choose to do.