Jump to content

topoff - air powered vs ph?


dchild

Recommended Posts

Hi

 

I've looked through a lot of threads about auto topoff systems (I've already ordered my float switch) but have been unable to find a clear advantage of using an air-driven topoff vs a powerhead. Is there a clear winner here? Here are some of the differences I can think of:

 

PROs

 

Air:

-doesn't hurt the pump to run dry

-can use battery-powered pump to reduce voltage through float switch

 

PH:

-pumps faster

-can use an open or imperfectly sealed container

-quieter? not sure about this, just my general experience with ph vs air pumps

-simpler

-easy to add a bigger reservoir if I am going to be away for a week, then switch back to the less unsightly small container when I'm around

-I already own a small powerhead and bucket

 

CONs

 

Air:

-need a decent size, rigid airtight container. I have a 5g glass carboy but it is full of homebrew and not topoff water :)

-without a rigid container, pressure in the reservoir can continue to pump water for a short time after the switch turns off

 

PH:

-running dry will damage the pump

-requires a relay and power supply to reduce voltage through the float switch

-??always takes water from the bottom of the container, so it will give off a heavier mix if there is kalk in the water??

 

So which route should I take? I am leaning toward the powerhead approach but am open to all suggestions.

 

Thanks for your time,

Link to comment

IMO, faster flow is a bad thing in a top off. You would rather add freshwater slowly to let it mix.

 

Like you, I had an extra pump lying around. So thats what I used.

Link to comment

I have an air powered top off. The biggest drawback is the relatively small container. The extra flow when the pump turns off is not that much of a problem even on my 2.5. I had an extra air pump so that’s what I used. If I was to do it again and I didn't already have an air pump I would go with a power head. A way to get around burning out the motor is to add a second float switch to the top off tank. If the water level gets too low it won't allow the pump to turn on. The only requirement would be a float switch that could be fully submerged.

Link to comment

I run a power head type and I don't use a relay never had a prob , I use the same float swich that californiareefs.com uses prety much the same set up but i built it my self. for the issue of your kalk settling get one more tiny ph and run it in the bucket to keep the mix stured up. oh yea I also have a ball valve inling to adjust the flow into the tank

Link to comment
The only requirement would be a float switch that could be fully submerged.

forgot to mention this the float switch I mentioned in the last post can be changet to normaly open or normaly closed by turning the "bobber" upside down

Link to comment

I have an air powered topoff. I like it a lot, but I've had a LOT of troubles getting everything the way I want it.

 

First, I used a polycarbonate water jug, which flexed too much and wouldn't seal right. Then I bought a 5gal glass carboy. Worked awesome, but the stopper was a PITA to get setup right and would leak after being removed from the carboy too many times. Finally, I ordered a different cap for the carboy (for a racking tube, with another plug covered opening for starting a siphon through the racking tube) and everything is excellent now.

 

For giggles, my topoff thread:

 

qfour20's air powered topoff

 

Incidentally, now that I'm using a battery powered airpump, the thing is almost totally silent. 5 gallons of topoff water will last me almost a week.

 

Good luck!

 

-q

Link to comment
  • 2 weeks later...

I have the same type DHoffroad uses sounds like. Nothing else needed but an extension cord and tubing if you already have a bucket and PH. BTW make sure you keep the supply to the main tank above the water line so nothing can back flow. ( Which ever way you go , make a snail gaurd out of a pill bottle.)

Link to comment

I went with a float switch with a relay to lower the voltage though the switch. I use a minijet 404 turned all the way down and it trickles into my sump. Works quite well, takes about 30 seconds to replace about 1/4 gal or less. I like this method because you can use something like a regular 5 gallon bucket and it will work fine, no need for an airtight seal

Link to comment

I built my own auto-topoff using a relay and float switch from Grainger, and a replacement windshield wiper fluid pump from an auto parts store. I power the pump with a small 9V ac/dc adapter from Radio Shack. If you get the right pump, it comes with its own mini-bulkhead type fitting, making it a snap to install in any plastic reservoir. I used a small square rubbermade type tote that held about 5 gal of kalkwasser. You can locate the wiper fluid pump above the bottom by an inch or so, so that it doesn't suck up the calcium hydroxide.

 

FWIW, I used this setup without the relay for several years with no problems- even if the pump ran dry for hours (maybe days!), but recent incarnations of this resulted in shorted out float switches if I didn't wire in the relay.

Link to comment

I used a air powered ATO for my 2.5 gallon here at school, and have a PH powered one for my 15 at home. Here is how I have them set up and what I like:

Air Powered

Battery powered air pump, 32oz Nalgene(no flex so no problem with built up pressure), float switch. I made this whole system my self, pros are the small size and simplicity matches the scale of the rest of the set up. Con: bottle is too small go through it in two days(MH and closed hood), solution, ordred a 128oz Lab style Nalgene with thick sides will be settin up this evening.

 

Power Head

I bought the switch wired into the cord from Cameron at californiareefs.com its works great. I have it mounted in my sump. Reservoir is a kitchen trash can, i fill it with about 8 gallons of RO water, it lasts I think a week and a half, I dont really know I would have to ask my father as its his job to fill it up when I am at school. I have a maxi jet 1200 and 3/4 inch tubing for the fill line. Pro: keeps SG stable, can leave for extended periods, Con: voltage going through tank. Also it would be harder to get a large container air tight (thought you can buy large nalgenes) and if you wanted larger outflow line than 1/8 I think you would need a larger air pump. If you were to use the 1/8 tubing it would take forever for it to top up, I know slow is good but i mean how slow.

 

Jerome

Link to comment

Try this:

 

Get a windshield wiper pump from your local autoparts store - I have found that a 1993 Probe model is good for cost, ease of instillation and pumping power

 

Find an unused wall-wart around 9-12 VDC - now there is no problem with voltage and current through the float switch

 

Find a non-polycarbonate container - in case you want to mix Mrs. Wages Pickling Lime or Kasswaser. Polycarbonate will break in time.

 

now connect everything togther and Eureka - a low voltage, low cost autotop that does not need to be airtight.

 

And you get to keep your powerhead for premixing your saltwater for waterchanges..... everyone does this, right?

Link to comment

Thanks all for your advice, after all this constructive input I have decided to go the powerhead route. I ended up using a pump for a fountain I built long ago (smallest Beckett pump) b/c it is only 60gph and you can turn it down from there. At first since it is only 10W or so I wired the float switch so the current was running through - big mistake. It stuck on and luckily I was checking every 5 min or so.

 

So I had to wire it up with a relay, got my parts from radio shack. I decided to make my own power supply (basic diagram at http://www.epanorama.net/circuits/psu_5v.html , you can leave out the voltage regulator and get away with a single capacitor, all it takes is minor skill with a soldering iron) but a 'wall wart' style would work just as well. I think I saved about $3 building it myself but it was fun and I think it looks nicer. I wired it up to a plastic box and put an outlet on it. For the floats I wired 2 float switches in series and clamped on a bit higher than the other as a backup.

 

Now it works like a charm, pumps slowly into my sump. Definitely nice not to require the airtight container, makes adding additional topoff water so much easier.

 

Thanks all for your input! I am sure my fish/corals appreciate the additional stability.

Link to comment

Wall wart

 

A small DC power supply in which the AC / DC conversion electronics is contained in a box that plugs directly into a wall power outlet.

 

These are seen growing from walls all across the world. They come from phone answering machines, scanners, USB components, Zip drives, cell phone chargers.....

Link to comment

Archived

This topic is now archived and is closed to further replies.

  • Recommended Discussions

×
×
  • Create New...