ATO in a large sump (100g rubbermaid)

[davidpesce]

Looking for any experience with ATO in large unpartitioned sumps.

Float valves seem to allow for too large of a window between fillings and setting an aqualifter to pump at intervals seems to be ok only if the reservoir is filled to the same height as when i calculated the rate of transfer.

Looking for creative ideas that people have implemented (failed and successful!).

 

[pascal32]

How big of a tank do you have connected? with that much water volume the salinity shouldn't change too much.

off the top of my head:

using a controller:

I would try putting in a double float switch (always have a backup switch) as a "high" level. set the controller to add ATO (with something bigger than a aqualifter, say maybe a LifeGuard QuietOne 1200 Pump with a 1/2" inline ball valve set to run every 30 minutes for some number of seconds. use the float switch to disable the pump when it is at capacity (safety). Add a low switch which activates the pump to run until it is at min level (shouldn't happen - have it send you a message so you can adjust the pump interval)

You will have to get it "dialed" in, but it should be more consistent.

for a switch you might want to touch base with Avast and see if their magnetic mount pressure switch can hold through the wall of a rubbermaid. regular float switches can not be near magnets.

alternatively I just checked and this will fit, though I would put a touch of effort into securing it as it is on its last adjustment: http://www.genesisreefsystems.com/proddetail.php?prod=04-000018-02

 

[pascal32]

I checked the avast sensor and it is a 1/4" up and down for 1/2" total tolerance which over a 48"x24" tank is 2.5 gallons

using this calculator: http://www.garf.org/calculators/EvaporationCalculator.asp

if you evap 2.5 gallons your salinity changes by about 0.5 PPT

I'm not sure if there is an "acceptable" swing number. I've heard no more than 1ppt per day - if that is accurate the .5 is likely a bit much for a daily event.

the above description should help stabilize, though there is some dialing in required.

 

[davidpesce]

You're right on about evaporating 2.5g a day. That's about what I lose depending on the season.

I have set up a float switch but the issue remains that it waits too long before filling. The aqua lifter at least fills it slowly as to not dump a ton of fw into the sump (like a larger pump would).

I typically over-engineer things but I like the idea that there must be a way to run an almost constant salinity. Plus it's a challenge. :0)

As far as the tanks hooked up, it's about 240g total in the system.

I'm thinking of partitioning the sump but with the uneven edges it's going to be near impossible with the tools I have at my disposal.

 

[kelso1980]

I know it's not a popular option, but i've always had luck with using a timer to turn on the ATO pump. I have kind of the same problem because I only have a 5G pico tank without a sump. float switches are not sensitive enough and they take up valuable take space.
It takes longer to establish how long the timer needs to be on and for how long but it's pretty unlikely to malfunction (knock on wood)
It also takes more monitoring especially during season changes.
But it's an option.

 

[kelso1980]

duplicate post... sorry

 

[Capt_Cully]

I know it's not a popular option, but i've always had luck with using a timer to turn on the ATO pump.

This is the set up I used for my new tank. In the past I used floats too. I see your issue with the large sump. I've been happy with the results. It requires closer monitoring for sure, but I trust a controller more than float switches.

 

[Conesus_Kid]

I have the exact same situation. I used a float valve, but it would clog over time since I run makeup water through a kalk reactor.

I since have adopted the KISS methodology and now have my RO/DI container elevated on a stand and dialed back the output valve to drip into the sump for makeup water. I do have to adjust manually every few days, but this has been the most reliable and consistent method.

 

[der_wille_zur_macht]

My preferred solution to this problem is along the lines of what Pascal suggested. Go with a hybrid approach.

Use a timed pump that's "close" to your daily evap, and use float switches to make sure it never gets too high or too low. Then, you can set up the time intervals to run the pump at an appropriate spacing/rate through the day, but you also get some safety from seasonal variations in evaporation rates.

Even if you did not have a controller, this would be easy to implement with an appliance timer and a relay.

 

[StashuDave]

My suggestion is to get a high precision peristaltic dosing pump in addition to using float switches. You can get a Reefiller type pump that only doses 3 gallons per day max and is highly reliable. Once the switch opens it may take 12 to 18 hours to replace your evaporation... Thats what i use and if you have a controller you could refine it even more.
Dave

 

[pascal32]

I like peristaltic pumps as much as the next guy, however for This water volume I would be concerned about the tube failing at a bad time. Regular pump should be more reliable, use two for redundancy, they are cheap

Did my first post make sense?

 

[captain7359]

I currently have a 75 gallon rubbermaid as a sump and previously had 20 long both of which I used the same dual float setup for. The float controls a relay to switch on/off a metering lmi pump. A couple months ago I finally added a time delay relay that once the float triggered the relay it would start the pump until the float rose enough to break power, but the relay has a timer that keeps the pump powered for another 10 minutes to keep the pump from short cycling with minor waves in the sump. My floats are pretty close to the one from aquahub below.

http://www.aquahub.com/store/madisonm8000.html

 

[davidpesce]

I was brainstorming this and kept thinking, "I wish I could make this laser-accurate." Well, apparently there are laser water level sensors. I'm going to take a look at some and see if they'll work.

 

[StashuDave]

Brain Fart.... The ReefFiller pump is a diaphragm pump, extremely accurate and long lasting. The one I'm using is well over 10 years old and still running like a champ. Only possible downside is that it is kinda loud... I always bury it in a garage or basement so it's not a problem in my situation.
I can see how you are focusing on getting a bullet proof float system... But my approach focuses on securing the rate of addition. My approach gives you the gift of time.... Weeks possibly to realize that there is a problem. Commonly if your float switch sticks on... Even for a short period of time, Disaster. With a 3 gallon per day pump, the pump could stick on for 2 weeks before anything overflows. If you have your 100 gallon sump 3/4 of the way filled, that leaves 25 gallons extra. Even if you have zero evaporation that's 8 days for you to realize that there is a problem. If you more realistically have 2 gallons evaporation a day that gives you more like 25 days to realize the pump is still on.
The reality is that any float can stick.... You need to have a pump that won't destroy things when the t eventually happens.

Dave

 

[pascal32]

there are optical sensors like tunze and autotopoff.com use. I've heard of laser float & IR, never caught any details through.

ether one kinda scares me a bit from a keeping clean perspective, though the opticals from Tunze seem to have good feedback

http://fluidswitch.com/pages/OpticalLiquidLevelSensorOS-900.htm
http://www.dwyer-inst.com/PDF_files/ols_iom.pdf

the pressure based switches make sense to me.

 

[GMaquarium]

This is the reason I don't like to use large tubs as sumps. Too many things working against you. Perhaps you could drill a large drain and have water spill out of the tub into a small aquarium 20-30gallon tank sitting on the floor next to it, with your return pump connected to that. Make a baffle to keep your level in a small footprint and use a pressure sensor switch type of ato.

Yes I am suggesting a sump for your sump.

 

[der_wille_zur_macht]

there are optical sensors like tunze and autotopoff.com use. I've heard of laser float & IR, never caught any details through.

ether one kinda scares me a bit from a keeping clean perspective

I agree with that. The "no moving parts" marketing gimmick used with optical switches doesn't automatically imply higher reliability. A snail wandering in front of it or enough salt spray can still cause failure. The most reliable liquid level switch is probably a capacitive switch, since it doesn't need to directly touch or "see" the water and there is literally no way to foul, stick, jam, block, corrode, or otherwise obstruct one. But they're expensive and IMHO plain mechanical float switches (like the common Madison M8000 series, which is what most or all of the reef vendors sell) are extremely reliable if installed and maintained correctly.

This is the reason I don't like to use large tubs as sumps. Too many things working against you. Perhaps you could drill a large drain and have water spill out of the tub into a small aquarium 20-30gallon tank sitting on the floor next to it, with your return pump connected to that. Make a baffle to keep your level in a small footprint and use a pressure sensor switch type of ato.

Yes I am suggesting a sump for your sump.

If you've got a submersible return pump, you can just plop the small aquarium right in the middle of the tub, and you essentially build a baffled "island" compartment for the return pump to sit in, without having to glue or seal to the tub.

 

[davidpesce]

Nate-you just sparked the perfect plan!

It's not a submersible sump but I can build something out of acrylic that can sit in one side of the sump that directly connects to the outlet of the sump via PVC. The walls of the inner box will be set to the perfect height in the sump. Wen the water evaporates it'll eventually lower inside this inner box and trigger a switch to pump new water in.

The the regular float valve or pressure switches will be more accurate. Hot digity, I like it!

Any thoughts or concerns against this?

 

[pascal32]

If you've got a submersible return pump, you can just plop the small aquarium right in the middle of the tub, and you essentially build a baffled "island" compartment for the return pump to sit in, without having to glue or seal to the tub.

I like the idea do you think the tank would have a disposition for floating away as the level drops if the sensor isn't far enough to the top? If that happened the pump would run dry.

Nate-you just sparked the perfect plan!

It's not a submersible sump but I can build something out of acrylic that can sit in one side of the sump that directly connects to the outlet of the sump via PVC. The walls of the inner box will be set to the perfect height in the sump. Wen the water evaporates it'll eventually lower inside this inner box and trigger a switch to pump new water in.

The the regular float valve or pressure switches will be more accurate. Hot digity, I like it!

Any thoughts or concerns against this?

only if the pump tries to pull up (if the above is indeed accurate) - this would cause stress on the glass where the bulkhead is. on a small say 10 gallon tank it doesn't take much to break the glass.

 

[der_wille_zur_macht]

You could just put something dense inside the tank/compartment, i.e. sand.

I probably don't need to say this out loud, but if you're using a switch-activated ATO (regardless of the style of switch) make SURE you've thought out a failproof design, i.e. use a backup switch.