float switch failure

[Subw00er]

Ya but a timer also has a failure mode. What if over time you dont notice the level and its cooler in the house so you get less evaporation than you initially calculated for. There is a chance for a slow overfill situation.

Floats really are the best way, you just need redundancy if you're going to use them. Grainger sells some higher quality float switches that are encapsulated if you are worried about snails or debris.

 

[Fishbulb2]

Ya but a timer also has a failure mode. What if over time you dont notice the level and its cooler in the house so you get less evaporation than you initially calculated for. There is a chance for a slow overfill situation.

Floats really are the best way, you just need redundancy if you're going to use them. Grainger sells some higher quality float switches that are encapsulated if you are worried about snails or debris.

If you don't notice your water level changing in the sump over the weeks and months it would take for top off system to get that out of whack with a slow peristaltic pump (like the BRS 50ml/min pump), then you will run into serious problems with any system. You don't need to match the top off exactly with evaporation. You simply tweak it ever couple of weeks by adding or subtracting a minute from the dosing schedule. It took me a couple minutes every two weeks or so with my AC Jr. Changes in your tanks evaporation rate won't happen that quickly. Now I use an autotopoff.com one and just have that on a timer with my AC. If my sump level ever starts to drop, it means add a minute to the cycle. If I ever see it above the marked line, that means the ATO would have failed and the timer is stopping it. No way I wouldn't miss that.

What I advocate is to place your float switch commercial ATO on a high quality timer. The timer serves two purposes, redundancy and convenience (that every time you stick your hand in the sump, you won't kick on the ATO). But for FWIW, i don't think the failure rate on a high quality timer is anything near that of the float switches.

FB

 

[Fishbulb2]

I would also add that you should also choose your dosing pump carefully when considering your ATO system to minimize any risk. What you really want to do is simply give yourself time to catch any problems when they occur. If you are using a large pump, then even couple minutes of excess dosing could spell disaster. If you are using a very low flow rate pump, like a peristaltic pump, you could give yourself hours to correct anything if you catch the problem. Ideally, you would want a pump (or drip rate for a gravity system) that is nearly always running to keep up with evaporation. That way if the whole automation system fails, you are left with a very slight and slow drift towards a higher sump level giving you plenty of time to catch anything.

FB

 

[Subw00er]

Actually, the timer + float is not a bad idea, and would reduce possible damage but if the float has failed, you'd still have to catch it before hell ensued! The timer would jsut lessen the blow I guess.

 

[Fishbulb2]

Yeah, you would need both to fail. In the case of most aquarium ATO, you would likely need two float switches plus the timer to go. Which seems unlikely.

I actually started running my ATO like this not for redundancy but to protect my pumps. I had a nice Buchler peristaltic pump before that I used for my ATO. One day I put my hand in the sump and I could hear the ATO viciously oscillating and it fried the pump. Now it only runs for 5 minutes every hour and it just seldom happens to overlap with me playing in the sump. I've had many a problem with ATO in the past but using a slow pump and limiting it's duty cycle have worked best for me.

FB

 

[nanomania]

thanks guys... ill go for 2 FW and connect timer........ plz guys can smone upload a diagram of 2 FS attached to 1 pump..

 

[nanomania]

HOW TO ATTACH ANOTHER?

 

[nanomania]

HOW TO ATTACH ANOTHER?

 

[DaveMorris]

http://www.spectrapure.com/St_alc_p3.htm

This is what I have used. It uses air pressure in the rigid tube to trigger a relay. Your little feather dusters would have no effect on it at all.

 

[reefgeezer]

If you wire it in series with the pump you do have to be careful that you use an electric float switch that will carry the required load. Many are rated only for very low amperage and are intended to operate a relay.

 

[nanomania]

ya,but where to attach another float switch??? sothe pump only worksif they both swichon together...

 

[nanomania]

any diagram?