Sump basics

tjbuege

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Ok, I know it's been a while since the last post on this thread... but I'm taking my time soaking this stuff in, and thinking about how I want to setup the sump.

I'd like to ask a few questions about evaporation and how to balance sump levels and aquarium levels. Right now, my 20 gal tank is open topped. It loses between 1 1/2 and 2 inches of water a week. So I'd have to assume a 50 gal tank in the same room will also lose up to 2 inches a week. That's a lot of water. With the way sumps work, it's the sump level that will drop as the tank water evaporates. 2" drop in a 50 gal aquarium is going to translate to a much greater drop in the sump. I know there are numerous factors that can affect evaporation rate. I might be able to make a few adjustments and slow that down, but that's not what I want to get into in this post.

Now...the balancing act part. If I want to avoid topping off the water in the sump every day, I need to keep the sump level up high enough to ensure there's enough water to handle a week's worth of evaporation, whatever that amount may be. But... and here is where I can't figure this out in my head... if I have enough water to handle one week of evaporation, what happens if the siphon in my overflow box breaks early in the week? I'll definitely have a flood, as there will be a lot of extra water in the sump to handle evaporation for the week, unless I keep the water level significantly below the top of the tank. That, I think, would not look good asthetically.

I've gone over this in my mind for a while now, and can't figure out what the solution is. Any ideas?
 

Gerryd

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Tim,

Just make a siphon break hole on the outlet so that as soon as the water level drops, it stops the siphon.

THEN you need to keep adding water to the sump and shutting the power off to ensure it is not too much.

Eventually you will reach a sweet spot where no more water can be added to the sump. That is your NEW fill line.

Is how I did it anyway. I had enough extra in my sump to go 3 whole days. A 180 in FL evaporates a lot...

Just add, shutoff, watch, repeat. This way you are THERE to watch what happens if the power goes out...
 

tjbuege

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Gerryd;75257 said:
Tim,

Just make a siphon break hole on the outlet so that as soon as the water level drops, it stops the siphon.

THEN you need to keep adding water to the sump and shutting the power off to ensure it is not too much.

Eventually you will reach a sweet spot where no more water can be added to the sump. That is your NEW fill line.

Is how I did it anyway. I had enough extra in my sump to go 3 whole days. A 180 in FL evaporates a lot...

Just add, shutoff, watch, repeat. This way you are THERE to watch what happens if the power goes out...

Hi Gerry,

Thank you for the response. BUT.... either you misunderstood my question or I'm misunderstanding your answer. :)

What do you mean by "outlet"? are you referring to some part of the overflow hanging on the back of the tank? or are you referring to the end of the return line coming from the pump that sits in the sump? I suspect this is what you are takling about. I actually fully comprehend the significance of a siphon break at that point. What I'm asking about is the necessary siphon tube, the upside down U, in the overflow box hanging on the back of the aquarium. In the scenario I'm concerned about, the power is still on, the pump in the sump is still pumping, but that siphon in the overflow box has somehow stopped siphoning water out of the tank and back down to the sump.

So... how can I make sure I have enough water in the sump to cover a week's worth of evaporation, while at the same time, not have so much water that it will overflow the aquarium should that siphon in the overflow box break. I could probably just run the aquarium level low enough to handle all the water, but would that look ok? I'm thinking I wouldn't like the looks.

But could the answer be as simple as this? Say I lose 2" of water a week (that's about 5.25 gallons in a 50 gallon tank), and I'm willing to top off once a week (I'm doing weekly water changes anyhow). So I run the aquarium level at 2" below the rim. Then, worse case scenario, I change water, making sure there's enough in the sump to handle the evaporation from the main aquarium, and the overflow siphon breaks without my noticing. The water in the sump will be pumped up to the aquarium, filling it to the very rim. Is that what I have to do? or is there a way to allow a higher level of water in the aquarium, yet minimize or avoid the danger of a flood should that siphone in the over flow break when there's still too much water in the sump?

Does that make sense?
 

Chunks

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I don't have time to write now but I have just setup a 55G tank with a 3ft sump and I can go a week with out refilling and that's with the water temp on 82-84F for discus fish. If you want some pictures I'm happy to show you m setup.
 

tjbuege

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Chunks;75266 said:
I don't have time to write now but I have just setup a 55G tank with a 3ft sump and I can go a week with out refilling and that's with the water temp on 82-84F for discus fish. If you want some pictures I'm happy to show you m setup.

Hi Chunks,

Thanks, pictures always help. Either post them here, or if you want to send them to my personal email, PM me and I'll reply with my address.
 

RukoTheWonderDog

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Tim-

You aren't going to find the magical solution to the problem of evaporation. A tank is going to evaporate, and you may find that you have to top off the tank more often with the sump, although as I already noted I don't see much of a difference in evaporation between the sump tanks and non sump setups. As you already said, if you overfill you risk an overflow when the pumps are off, and if you don't top the tank off, you may run your pumps dry. An auto top-off system can add a huge level of complexity, as your water parameters (ferts, hardness, alkalinity, pH, etc) can be affected if you have water constantly being added.

Lately, my 180 gallon has been losing about 2 inches from the sump level a week. That's not a whole lot different than my other tanks. The benefit of the sump setup though, the water level never drops in the tank, and even if my sump level is down to the absolute minimum, the tank uptop is still full. From my 'max' water level the water in my sump has to drop nearly 7 inches before I risk running the pumps dry.

I guess I don't really follow what the issue is here? Are you concerned about having to top off the sump more often?
 
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tjbuege

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Hi Ruko,

RukoTheWonderDog;75270 said:
I guess I don't really follow what the issue is here? Are you concerned about having to top off the sump more often?

Yes, that's exactly my concern. In the aquariums I have now, I like to run the water level as high as I can. They are both All Glass aquariums (20 gallon long and 29 gallon), both with a typical hang on back power filter. The 29 gal still has a hood (Eclipse 3 hood system actually), so evaporation is not an issue there. But my 20 gallon has been "hoodless" for a couple years now. I'm considering a new tank (50 gallon; 36x18x18) and would like to go rimless, and thus without a top or hood. I'm a bit concerned about how the tank would look with the water line at 16" or less, instead of closer to the top (I was hoping for 1" below the rim).

So what I think I'm beginning to understand is, if I want to only top off the sump water once a week, the water level in my aquarium needs to be determined based on the rate of evaporation I see in my home. So if I see 2" of evaporation a week, then I cannot have the water level any higher than 2" below the rim. Is that correct? Is there any way around this so that I can have the aquarium water level higher, but still keep enough water in the sump to handle the evaporation for a week? It sounds like the answer is "no".

There's still a part of this question I have unanswered (I think): If I use a 20 gallon high (24x12x16) for a sump on the 50 gallon aquarium, 2" in the main aquarium equates to about 4 1/2" in the sump. So I would need to make sure I wouldn't pump any more than that in the event the siphon in the overflow breaks. That's not a lot of water in the sump, in my opinion. The pictures I've seen of sumps have a lot more water in them than that. Could it be because the overflows in the main aquarium are drilled and do not require a siphon, thus eliminated that particular flooding potential?

I appreciate all the responses. This is continuing to be a helpful thread.
 

shoggoth43

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For your concerns...

You would need to run lower in the main tank. The U tube is potentially a problem. Always will be. It's the nature of the beast. You can minimize the risk of a U tube losing siphon by a properly designed overflow box which always retains water in the U tube. You also minimize the risk by making sure you have enough flow THROUGH the tube. If you see any slow flow through the tube where tiny air bubbles are collecting in it anywhere, then you don't have enough flow through it. Either increase the flow from the sump, or decrease the diameter of the U tube slightly. Say going from 1.5 " to 1" or whatever. That will increase the velocity and keep the tube clear of air. It also reduces the max flow, so you'll need to play with it a bit. Also, make sure you don't let algae build up in it.

In all fairness, while I appreciate the very real possibility of disaster should the tube lose siphon, I honestly feel that you are perhaps overly concerned with this particular failure mode. I have had a U tube lose siphon exactly twice. Neither of these were a complete loss of siphon and I KNEW that air was building up in the tube. Neither time caused a flood. IF this is a major concern for you, I would suggest a hybrid approach. Build in enough for a long weekend. Then add as needed midweek. This will let you check the U tube, the prefilter sponges, and whatever you need to ensure proper operation.

I will also leave you with my unexpected surprise. During the recent power failure my siphon break failed to operate as expected. The siphon break is a wide nozzle on a 1/2" locline. The nozzle is just about 1/2" under the water surface and typically breaks quickly. For whatever reason it did not do so during the power outage. I suspect some aromatica floating around got sucked up when the flow reversed and prevented air flowing in until the main tank had drained down 3 inches or so. Had I been running the sump levels at their "typical" max level such as you suggest you'd like to do, I would have had a flood. BTW, the BBA choked U tube never lost siphon and is running just fine in its current state.

I bring this up only to point out that it really doesn't matter how many times you test something. Something stupid ALWAYS seems to find a way to happen. If you plan on running at a max level somewhere, you can expect a failure in ways you never anticipated. Whether this is a cracked bulkhead fitting, a snail, a discus in the overflow, a cory clogging the overflow line, a feline induced issue, or an in-law induced failure, you can't plan for them all. Until you get a much better feel for the system and how you can expect it to fail I feel that you'd be better served with forcing yourself to stay on top of things. Keep less water in the sump for now until you're flat out sure everything is fine. Even then, expect that at some point, something improbably dumb will happen.

-
S
 

tjbuege

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feh;75291 said:
Why not just use an auto top off system?

Hi Feh,

Yes, I'm aware of that option. I don't want to add too much complexity at this point, until I understand things better. Thanks for the suggestion, though. :)

shoggoth43;75295 said:
In all fairness, while I appreciate the very real possibility of disaster should the tube lose siphon, I honestly feel that you are perhaps overly concerned with this particular failure mode.

shoggoth43;75295 said:
Until you get a much better feel for the system and how you can expect it to fail I feel that you'd be better served with forcing yourself to stay on top of things. Keep less water in the sump for now until you're flat out sure everything is fine. Even then, expect that at some point, something improbably dumb will happen.

Hi Shoggoth43,

Ok, that was a very diplomatic and gentle way of saying " DUDE! You're over analyzing this!" :D Exactly what the doctor orderd, I think. ;)

Seriously, you're right. I do tend to over analyze, over plan. I need to just dive in and get my feet wet (not literally I hope). Experience goes a long way. I think maybe I'll start by setting up a 10 gal sump on my 20 gal tank, for practice, and to see how things go. Then I'll have a better idea what I want for my 50gal when I get around to finding a place to put it.

Thanks for all the suggestions and feedback. It's truly appreciated!
 

RukoTheWonderDog

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You'll be fine. I've seen some pretty horrendous plumbing setups that have never had a catastrophic issue. Your head is going in the right direction, and your hang up on these things tells me that you're going to have a well planned, well thought out setup.

If you are planning on using vinyl tubing, give all the SS clamps a good check before filling and running the sump ;)