Gravity ATO question

[JDubb_4051]

New guy here so pardon any ignorance


Working on planning plumbing for my tank and setting up my ATO. Everything I’ve read is gravity fed can be dangerous if float shutoff gets stuck. Makes sense. Prioritizing my dollar, looking to see where I can get by for a short time until I can upgrade later.


My sump (EShopps rs-100) has a cut out at the top of the skimmer/return chamber divider that is about an inch below the top and about 8 inches long. I believe this sump has a 20 gallon capacity and under running conditions will use 10 gallons.


So... my hypothesis is a gravity fed ATO tank with no more than 5 gallons would be okay in the event of a stuck float because....


- water would overflow to skimmer chamber IF continuous stream exceed what return chamber could hold.

- if only half the capacity is used, I have buffer if the entire ATO source emptied. Given an estimate of 1 gallon a day, it seems a very slim likelihood I truly dump all 5 gallons....especially with a new tank and no refugium.


I suppose I should make sure that a full 5 gallons (if needed) would only fill skimmer and return chambers but that aside...any holes in my logic?


Eventually I want to feed my ATO from my RO/DI supply and same with AWC to salt but not without many layers of redundancy.

 

[Hemmdog]

Seems risky lol. 5 gallons of RODI would swing my(90gal) salinity hardcore, throwing off all your macro elements.., acros would die, tears would be shed. How big is your display and what all do you have in it ? Check craigslist or something similar or even the marketplace here. People sell them all the time. I recommend tunze, they are reliable.

 

[JDubb_4051]

Thanks! I’m setting up a 75 gallon DT and have yet to fill it with water (waiting on RO/DI system) so I’m still in the planning stages.

The chemistry change wasn’t something I considered obviously so that’s a good point. Would 5 gallons (at most) across 85-ish (with sump) throw numbers off that much?

 

[JDubb_4051]

Sorry. Re read your response. 5 gallon over your 90 would swing.

 

[Hemmdog]

Thanks! I’m setting up a 75 gallon DT and have yet to fill it with water (waiting on RO/DI system) so I’m still in the planning stages.

The chemistry change wasn’t something I considered obviously so that’s a good point. Would 5 gallons (at most) across 85-ish (with sump) throw numbers off that much?

If you have easy stuff like zoas and some lps it might be fine but sps wouldn’t like it at all. It wouldn’t be good lol. Don’t do it lol. You will find a legit ato for cheap, I have faith

 

[JDubb_4051]

Really appreciate the response. I know something like the auto aqua ATO/AWC would be my best bet. Will either bite the bullet and buy it now or start poking around CL (buying used always makes me nervous)

 

[Hemmdog]

Really appreciate the response. I know something like the auto aqua ATO/AWC would be my best bet. Will either bite the bullet and buy it now or start poking around CL (buying used always makes me nervous)

Anytime!
There’s gems on Craigslist. Takes some searching, but the’re on there, haha.

 

[Captain Quint]

Welcome to R2R buddy.

Looks like @Hemmdog has you covered.

 

[griseus]

Hi.

I've been using a gravity feed ATO for 3years using a float valve. This is my long opinion/review.

The way my ATO works is a constant slow dripping which keeps the return chamber at the exact level all the time. If the float valve would to get stuck on the off position, the water level in the return chamber would of course lower and you risk running dry. But the risk for a flood from what i've noticed is extremely small and has never happen to me personally. Maybe i've just been lucky who knows.

First of all the floating part on mine is around 1" from the wall it's attached to. So a snail for example would first have to crawl out the water, then across another part, down to the water again and find the perfect spot. It also has to be a big snail that would have to press itself in to keep the valve open. And a small snail that can easily crawl in would not do any harm Unless it blocks the hole and stops the dripping( again running dry risk) which can also happen with electronic ATO. I know Tunze etc are great and reliable products. But because of cost i decided to try this and found no reason to change.

Anyhow. For me this have worked almost flawlessly and i've had it stuck only once on the on position, and still no water trickle because the hole was clogged with salt creep. So even stuck ON there was no risk for a flood, and salt creep would not be able to keep the hollow air filled plastic from float/close if i poured in water to the set level again, it would stay clogged.
You just can't get more water in the chamber than the height you have the valve set at, i honestly can't see how that would be possible. But please correct me if i'm wrong.

I might also add that i turn off my return when feeding which means the valve stays submersed 10min daily, and still only one clogging in 3 years using the same one the whole time. So i would absolutely recommend a gravity feed, and you save alot of money as well.
Just keep it clean like you would with any ATO and you're good.

 

[JDubb_4051]

I was thinking along the same lines as you (distance from wall and inherently out of the water) but being a newbie figured I had to be missing something.

I’ll likely add the AWC/ATO system in a few months.

 

[RandU]

I use a 15 gallon resivour gravity fed into my 180gallon sump with a float valve. I wouldn’t have it any other way. Far less to go wrong or fail.

 

[griseus]

I don't think we are missing something though. I've had this ATO running for a longer time and like i said never once have i had it flood, just stuck once and still there was no risk what so ever. But of course use a product you feel safe with. I feel 100% safe with my gravity feed, and if i need to replace the float valve eventually we are only talking 5-10$.

 

[griseus]

I use a 15 gallon resivour gravity fed into my 180gallon sump with a float valve. I wouldn’t have it any other way. Far less to go wrong or fail.

I feel the same. And it's very cheap simple to install and maintain.

 

[JDubb_4051]

Part of regular maintenance seems like a good way to think about it. What’s another $10 every six months/year

Thanks everyone

 

[RandU]

I really don’t even plan to do it as part of regular maintenance. I will probably change it when, or of it ever, fails. The amount of fresh water it will add to you system will not swing the salinity that drastically. On 100 gallon tank @ 1.025, 5 gallons of fresh weather would drop it to a hair under 1.024.