How do I calculate evap?

[nate82]

Could someone help me I plan on making an ATO but I need to calculate evap first Thanks

[rick s]

Hi Nate,

I don't know that you can. There are too many variables such as the humidity level of the room the tank is in, type of lights, duration of lights, fans, etc.

Is your 15 gallon up and running?
What type of ATO are you planning on using?

If you can give us more info on your set-up, people with similar systems can chime in with their rates.

[Horace]

If you need to calc evap, then the design of your ATO is flawed. It should replace the water as needed, not as calculated. If not, you are destined to either burn up a pump, or cause a flood.

[areze]

yep... ATO have electronic sensors or a float valve like a toilet bowl. mechanicly open the valve to let water flow in from gravity, or electronicly kick on a pump to transfer. then in both cases seal off, or turn off when its full.

you cant possibly assume you will lose Xgallons of water a day, and that this pump will replace X gallons if run for Yminutes.

[aastretch64]

What I have done is to make a mark on the sump when filled to max level, wait 24 hours, check the level again and refill to the mark measuring how much water I put it.

This is a general figure as evaporation can change on a daily basis, but I know that I lose about 1.5 gallons a day on my 90 gallon.

Then what a do is pump water from my basment set on a timer to replenish the lost water.

My pump runs 6 times a day for 7 minutes at a time to replace 1.5 gallons lost. So far it has been accurate as my water level in the sump only varies 1/4" at times.

Good luck

Alex

[miwoodar]

I agree with these other folks that you probably don't need to calc your evap. Some people top off with liter meters and such but the seasonal variations in evaporation rates can play havoc with dialing them in. Also, if you go away on vacation and you have a really humid or dry stint, you might end up overshooting or undershooting your needs.

Melev has a good writeup on an ATO that runs with a topoff switch. The parts are rather small - you could probably squeeze it into your 15 if that's what you need it for. http://www.melevsreef.com/plumbing/auto_topoff.html aastretch65 - you could easily add this to your setup JIC something happens.


I'm evap'ing between 1.5 and 2 gallons per day from my 65 right now.

[tundra1000]

Depending on your climate the top off amount will most likely change seasonally. Unless it is automatic it will need to periodically tweaked.
(winter is typically much dryer)

[nate82]

well my LFS said that he just has a gravity fed one that just drips all day with a valve and you open or close it based on how much water will evaporate... My set-up is just a 15 gallon long with T5's so not much evap but I need something for going away and I really don't want to spend $60 on something that will end up needing the same tweaks as a gravity fed one...

[reef_only]

you can mark your water level and after 24hours refill and what ever the water you put in that is amount of evap. If more accurate is needed then you need to do over many days as climate has big effect on evap. Other way is to tune up your ATO drip rate, start from somewhat low rate and monitor and increase the drip rate until you don't see the water level goes outside of range it should be. In reality you will see the water level at the low range on the hot&dry day and at the high range on the cold/wet day....

[miwoodar]

<a href=showthread.php?s=&postid=12875846#post12875846 target=_blank>Originally posted</a> by nate82
well my LFS said that he just has a gravity fed one that just drips all day with a valve and you open or close it based on how much water will evaporate... My set-up is just a 15 gallon long with T5's so not much evap but I need something for going away and I really don't want to spend $60 on something that will end up needing the same tweaks as a gravity fed one...

Shhh! That's what I use but people get flamed for float valves around here! If I had to do it again though, and I will someday, I would choose a dual float switch/powerhead design. If you use a float valve, make sure to set it up in a manner to allow you to ram a toothpick through it every once in a while (every two months or so). Otherwise, especially with kalkwasser, it will eventually clog when you least expect it.

[nate82]

exactly a float switch just seems like more work.. I don't mind playing with drip rates but if I'm going to spend $60 (I'm cheap) I don't really see the benefit of a float switch.. that can fail.. gravity can't

[rickh]

<a href=showthread.php?s=&postid=12877574#post12877574 target=_blank>Originally posted</a> by nate82
exactly a float switch just seems like more work.. I don't mind playing with drip rates but if I'm going to spend $60 (I'm cheap) I don't really see the benefit of a float switch.. that can fail.. gravity can't

Yes but you can end up with a fresh water aquarium!! R

[OliverM3]

<a href=showthread.php?s=&postid=12877292#post12877292 target=_blank>Originally posted</a> by miwoodar
Shhh! That's what I use but people get flamed for float valves around here! If I had to do it again though, and I will someday, I would choose a dual float switch/powerhead design. If you use a float valve, make sure to set it up in a manner to allow you to ram a toothpick through it every once in a while (every two months or so). Otherwise, especially with kalkwasser, it will eventually clog when you least expect it.

I've never had any problems with my Kent floats I guess the one I'm using on my 76 has been in the sump for about a year now with no clogs. I've moved my Kalk to a dosing pump through a stirrer so I guess that helps.
I evaporate about a gallon a day and keep my sump full with about 15g so really even if it clogs It would take me almost 3 weeks to run dry.

And it's not like I don't stick my head in there every morning before work to check things out anyway :)

[miwoodar]

I just got back from a 10 day vacation...

I had been evaporating between 1.5 and 2 gallons per day for quite some time. A lot of dry hot days hit while I was on vacation though and I ended up evaporating 2.5 gallons per day. If I were running a liter meter top off set to 1.75 gallons/day I would have been 7.5 gallons behind by the day I returned...and my return pump would have been fried.

[nate82]

I would only really use it in the winter and the heat in the dorms would be pretty constant... but i got it figured out so i'm good thanks though

[das75]

Been using a humidifier float valve from HD (~$12.00) for a couple of years and zero problems.

Mine is hooked direct to my ro/di but could also hook it to a container above the sump.

Regards to the humidifier float valve, I alway figure must be safe as sure there's way more of them on furnaces than reef tanks and I've never heard of one causing some ones basement to flood (heard of them not opening on a furnace).

[nate82]

wow das... not a bad idea... maybe i could rig something up... hmmm thanks

[areze]

I hope you didnt hook up a drip lol, been tried, its just a matter of time for it to fail.

float valves atleast work perfect untill they dont.