Vacation top off

[Paul B]

My tank, like most tanks use an auto top off that usually works great, but the last time I went on vacation, a bubble got into it and the tank sitter didn't notice the water level went down 7" which of course killed all the corals near the top of the tank.
So I brought back the device I used to use before I had an auto top off. It is just a plastic 2X4 or a real 2X4 or piece of plywood could be used.
I just drill a hole in it that will fit the top of a 5 gallon water cooler bottle that I happen to have laying around.
I put the plastic top on the water cooler bottle that comes with it when it if filled with water after I drill a 1/2" hole in the cap.
Now I just fill the bottle and invert it over the tank. (The batteries are just in the picture for the demonstration)

I make the hole in the 2X4 so that the bottle neck just touches the water.
As the water level goes down, air enters the bottle and the water level in my tank stays level. This will fill my tank for 8 days and I have been using this for decades with never a problem.
This is exactly how it works in a water cooler.
If you like, you can also put in whatever you want to dose for the week.

http://i258.photobucket.com/albums/hh270/urchsearch/IMG_2427.jpg

[Breadman03]

I'm going to slap myself now. I have a small cooler bottle sitting in my basement next to some 2x4's. I don't have a cap, though. I guess I could always buy a new bottle if I don't come up with a decent solution.

I'll see if it fits over my sump in a little bit.

ETA: it doesn't fit. I'll be checking out some different bottles next time I go to the store.

[MuldoonJT]

Sounds like you need a new tank sitter! How would one not notice a 7in drop in a small tank like that?

[der_wille_zur_macht]

For the record, I would be careful about using polycarbonate bottles for dosing, as there have been many anecdotal reports on this forum of people having them degrade and fail after exposure to kalk and other extremely basic solutions.

[uncleof6]

Although this would work for a fresh water system, with a salt water system, the chemistry just does not work out. Because the top off water is in contact with the salt water at all times, salt from the tank water will mix into the water in the container. Water level in the tank would remain constant, however the salinity would drop initially, and once the "reservoir" was empty, you would be back to the original salinity.

The concept of an ATO is to keep the salinity constant, however, this method does not achieve that. A variation in salinity, stresses the critters, even if over a relatively short period of time. Redundant fail safety, either electrical for mechanical systems, or mechanical for electrical systems is the solution; adding to the passive fail safe of sufficient volume in the return section of the sump to allow several days of operation without the pump burning up. In most situations, the pump is going to go, before you lose 7" out of the tank.

[Paul B]

I'm going to slap myself now. I have a small cooler bottle sitting in my basement next to some 2x4's. I don't have a cap, though. I guess I could always buy a new bottle if I don't come up with a decent solution.


You can go to Home Depot and buy a rubber cap that is used for capping a pipe. 1 1/2" or 1 1'4 pipe size should work.

Sounds like you need a new tank sitter! How would one not notice a 7in drop in a small tank like that?


Yes, especially when the two powerheads were splashing water all over the place. It boggles the mind doesn't it. But it was my fault also. I just told her to feed the fish and she knows absolutely nothing about a tank. I did however put a big sign on the tank with a large arrow pointing to a bottle of water and I said, if you can see the surface of the water through the glass, add the water. It still didn't work.

Although this would work for a fresh water system, with a salt water system, the chemistry just does not work out.

Oh contraire my good friend but it does work and as proof, my 42 year old tank is still functioning and I used that method for years. That is the reason you don't just invert the bottle over the tank without a cap. If you did that, you would be correct and the water in the bottle and the water inthe tank would mix thus dilluting the water in the tank. But the 1/2" hole drastically slows that process. I usually also install a short tube into the hole which makes it easier to adjust the water level of the tank. The tube allows me to build it easier without having to be to exact with the hole size in the 2X4.
Remember this is only a back up for me because I do have an auto top off.
My tank is 100 gallons so even if all five gallons went in my tank (besides the tank overflowing) it would not drastically alter my salinity. When the water level dropped 7" that increased my salinity plenty but nothing was affected except what was out of the water.
So adding a short 1/2" tube into the bottle will insure that the fresh water in the bottle and the tank hardly mix. If you want to make sure hardly any fresh water mixes with the salt water before it is added, you can insert two 1/4" tubes into the bottle. One a little shorter than the other. This way almost none of the fresh water from the bottle will contact the salt water before it enters the tank.

In most situations, the pump is going to go, before you lose 7" out of the tank.

My top off is gravity fed and does not use a pump.

[uncleof6]

The return pump in the sump will burn out before you lose 7" out of the tank.

[Paul B]

The return pump in the sump will burn out before you lose 7" out of the tank.


Oh you mean the return pump, I am sorry, I thought you meant the pump on the ATO.
Yes, if your water level dropped that much in a sump, the pump would most likely burn out.
I don't use a sump so I don't have a return pump. Sumps were not invented when I set up my tank, but if you are using a sump, this bottle would need to be in the sump.
In my tank, with no sump, the water level is very noticeable and I need a reliable way to insude water enters the tank. My system uses a 1/4" tube that travels about 40' from my workshop, over my ceiling to a float switch on my tank.
I also use this bottle method on my blackworm tank. But that is only 3 gallons so a soda bottle works and that is freshwater so I just leave the top off the bottle.
Remember, this is only a back up when I am away for an extended time.

[zakstrong]

very clever i like it. have you considered going even smaller. like 1/4 line. just to slow the osmosis even more.

[Paul B]

A 1/4" tube won't work by itself but two of them will work as long as one is slightly longer. Air will go in one and water will come out the other. But I have found that one 1/2" tube works well.
There is almost no mixing of freshwater with saltwater with this set up because saltwater weighs more and doesn't "want" to travel up the tube to the freshwater resevour.
Saltwater weighs about 64 lbs a cubic foot and freshwater is about 62 lbs a cubic foot.

[zakstrong]

i think the mixing has more to do with osmosis. the salt dissolved tries to go to the place with a lower concentration. But i would agree that it would be minimal

[SGT_York]

Saw this setup before during my college days, the salt content didn't mix into the freshwater he used about 18" of 1/4" tubing. not enough to be concerned in a 55G tank, in a nano probably not the safest.

[gbru316]

the same principle has been in use for years by those of us with nano tanks. Small animal water bottles with the bearings removed take the place of your jug.

Experiments have been performed, and it was determined that no appreciable mixing takes place.

[der_wille_zur_macht]

Experiments have been performed, and it was determined that no appreciable mixing takes place.

That's good to know. I was just going to suggest that it would be really easy to put this all to rest by simply testing the water, but if someone already has, all the better.

[Paul B]

I just put the thing on my tank with a small modification. I used a rubber end plug from a plumbers supply and inserted two 1/4" acrylic tubes into the end plug. One is slightly higher than the other and they just barely touch the water.
I am sure no mixing occurs. Besides, salt water is heavier than fresh water and doesn't want to go up into the bottle. It has been working great for me while I am away for a week or so.
I don't use it all the time because I don't need it but for certain times, it is a fail safe way to go.
If you don't like it, or don't trust it, just delete the post and go out to dinner. :beer:

[bigpuffer1]

very interesting im going to try it. i am leaving for vacation in a few months and i am going to try to set it up as a 2nd back up.

wow 1971?!!

[MuldoonJT]

The return pump in the sump will burn out before you lose 7" out of the tank.

I assumed he did not have a sump. As an easy fix would just be a bigger sump to handle the evaporation longer.

[Paul B]

I don't have a sump. I guess he did.

[mr.maroonsalty]

I remember Brian Plankis does something somewhat similar with an airtight container with a drain and an airline that opens the airway to the vessel when the sump level drops and seals the air off when topped off.

[Mike31154]

I'm in the 'keep it simple' camp for ATO as well. Unfortunately since I don't have the room above my display to mount a 5 gallon container, (also have a sumpless tank), I'm unable to use this method. My ATO therefore includes a couple of electrical components - a timer & an air pump. The timer runs the air pump for a few minutes each hour. The air pump pressurizes a glass wine carboy filled with top off water. The carboy has a rubber plug with two holes holding one short & one long rigid tube. The air pressure pushes the water from the carboy through a mechanical float valve into the display. Keeps my tank topped off for about 6 days. Ocassionally I'll add some alk, calcium or mag to adjust water paramenters. System has been bullet proof for years. Every once in a while I'll pull the mechanical float valve out of its mounts to ensure a good stream of water is coming out of the line.

I've been looking for a way to extend the top off period for more than 6 days. I haven't found any larger glass carboys yet. Might be feasible to use Paul's method to temporarily augment my air pressure rig when I'm away for 7 or 8 days. All I would need is a gallon or so.

7 gallon glass wine carboy. Air comes in tubing on left. Water pushed through tubing on right.
https://tsl4pa.blu.livefilestore.com/y1plv3z3dv_aHq-4Oo0K2hFYefxqhGjpAdtsHyh4rW8W46FJtCACDk6YqrZOcMQiunQnJZJRglUauc/Carboy.JPG?psid=1

Mechanical float valve mounted to rim of display. 'Wait' brand normally used on forced air furnace humidifiers. This is an old photo. I've since cut one (maybe even two?) of the float chambers off the end to make it shorter & reduce the in-tank footprint. Still works great. It has an adjustment wheel on it as well, for minor level adjustment.
https://tsl4pa.blu.livefilestore.com/y1pHKTvnfROs8jp-kZ91tlLcIikeV8XIg9rdyCGXzpJL_UrwpTJeg-oZv9flA9M-rzBr7ct-zhjFWg/FloatValve.JPG?psid=1

[Breadman03]

Mike, you should be able to just plumb another wine carboy in series with your current setup. Think about it as an ATO for your ATO.

[Mike31154]

Mike, you should be able to just plumb another wine carboy in series with your current setup. Think about it as an ATO for your ATO.

Ha, ha, thanks. Funny that you should mention this. I actually had thought about trying this as well. I'd have to test it a bit before trusting it. I'm having to cancel a backcountry ski trip starting this weekend due to my daughter not being in town to look in on my tank & changing out the carboy for me. Now is not the time to engage in such an experiment. Not sure my little air pump is capable of keeping two of these pressurized properly & I'd need to work on the timings. Even if I did have an ATO capable of going for more than a week, I still prefer to have a living, breathing human looking in on the tank, daily if possible. Someone with a little knowledge of the set up of course & my daughter is very capable.

[Mike31154]

Decided to try the 2 carboys in series and by golly it seems to be working fine. Running since last Friday afternoon keeping display topped up nicely. Bottle 1 was already down a gallon or two when I hooked up a full bottle 2 upstream of it. Pretty much a carbon copy of bottle 1, with a short tube delivering air & a long tube almost touching the bottom to transfer the liquid & once empty, more air pressure.

First thing I did was transfer sufficient water from 2 to 1 to almost fill it. I used the air pump to do this with both stoppers fully inserted into the necks of the bottles creating air tight seals. Transfer was going fairly slow so I released the stopper on bottle 1 to prevent air pressure from building in there until the transfer was complete. This speeded the transfer although it was still slow going with the small diameter tubing & low volume air pump.

Once bottle 1 was close to full I reseated the stopper & marked where the water level was. I ran the air pump to pressurize the new setup & ensure water was being pushed to the mechanical float valve in the display. Then I put the air pump back on the timer. It has 20 ON/OFF programs & I adjusted the run time for each program to 4 minutes for a total of 80 minutes in a 24 hr period. I'll see how that goes when both bottles get close to empty. Providing everything seals properly, it should be sufficient to maintain pressure until both carboys are empty of water.

As of today there's about a gallon of water in bottle 2 & bottle 1 is full. The water dropped a fraction in bottle 1 on the first day, but since then has held steady. I assume the air pressure has reached an equilibrium between the two bottles & the level in #1 will remain constant until #2 is empty of liquid & contains only air. We'll see what happens in the next few days.

It's interesting to note that I can actually monitor the evaporation rate by watching the short line in bottle 1 which receives water from bottle 2. There is a steady drip of 1 drop about every second coming from bottle 2. Although you can tell when the mechanical valve is dispensing water also, it's not as obvious & you can't count the drops since the water trickles down out of the valve.

Thanks again to Breadman03 for rekindling this idea & getting me to actually try it. If this continues to work successfully, I'll have an almost 2 week ATO!

Sorry to PauB if I'm hijacking the thread.... but my posts are still on topic about ATO right?

[Paul B]

Sorry to PauB if I'm hijacking the thread.... but my posts are still on topic about ATO right?



No apologies needed, you can never hijack my thread because they all go all over the place. I just came home from the Florida Keys and I had my vacation top off on the tank. No problems at all

[Mike31154]

Decided to try the 2 carboys in series and by golly it seems to be working fine. Running since last Friday afternoon keeping display topped up nicely. Bottle 1 was already down a gallon or two when I hooked up a full bottle 2 upstream of it.

So here it is, Sunday evening and the two bottles in series is now down to the last gallon of water, still keeping the display tank water level.... level. Should be good until tomorrow when I plan a water change. Perfect timing. Still can't quite get 14 days out of this set up, but it's nice to know it works for at least 10 days.