Bar none, your skimmer. Many have a habit of belching water on a restart or power out. I have a way to cope with that. a) Put little sections of tubing on the ventilation nipples and aim the little hoses back INTO your tank. Do not let them touch the water or your Venturi action will slow way down. or b) set your skimmer IN your sump so if it does overflow it will simply belch water back into the sump.
Your ATO if you don't secure your topoff line in some way that absolutely cannot flip out (causing your ato pump to keep sending water until the reservoir empties.) OR b, quite rare, but there's a reason to have a dual float or some mechanism that prevents an over-fill by cutting power to the ato pump. I don't have a controller---but I do have an over-fill-proof system.
Tank leak. THe nightmare that delivers the whole mess onto your living room carpet. Take any crack seriously, do NOT install a tidal surge wavemaker in a thin-walled tank, be VERY sure your tank is level before and after you fill it (stress adds up) and do not use a thin-walled tank in the first place, over 30 gallons. When you start reaching 50, that glass needs to get more substantial. My own glass is 5/8ths inch thick on a 105.
A check valve on any line: check valves allow water to flow only one direction and they sound like a real good idea---unless they clog. Because our systems produce a calcium carbonate in such places, and it clogs, do NOT use check valves. A gate valve is fine: those don't clog, and you CAN insert one in your return line to valve down an over-kill return pump to a more moderate flow. THis does not hurt your pump.
Another flood source is a pump turned off, while in a container that sits lower than the other end of the hose in the tank,---or higher, if you happen to have your pump in the tank and have a drain hose going down lower. Pump off, water continues to flow because the water in the hose has set up a siphon suction via gravity. A lot of people get surprised by this one. If this confuses you, diagram it till it makes sense.
Downflow box almost NEVER causes a leak UNLESS you let loose hair algae drift in your system and it clogs your overflow teeth, leaving the return pump sending water up faster than the overflow box can drain it down.
A power failure will NOT overflow a proper sump and overflow box setup, because the sump is filled in a power-off condition, and never filled more than that. A good downflow box is doublewalled, with a high inside wall that LIMITS how far the tank can drain down to about an inch or so. Once that limit is reached, the inner wall serves as a dam. If you've never set up a sump before, get a friend to shout stop at you if you are about to overflow.
And---if you are running ro/di---set a timer! A loud one!
It is also not a bad idea to install a nice loud water alarm in areas where you have a concern.
Your ATO if you don't secure your topoff line in some way that absolutely cannot flip out (causing your ato pump to keep sending water until the reservoir empties.) OR b, quite rare, but there's a reason to have a dual float or some mechanism that prevents an over-fill by cutting power to the ato pump. I don't have a controller---but I do have an over-fill-proof system.
Tank leak. THe nightmare that delivers the whole mess onto your living room carpet. Take any crack seriously, do NOT install a tidal surge wavemaker in a thin-walled tank, be VERY sure your tank is level before and after you fill it (stress adds up) and do not use a thin-walled tank in the first place, over 30 gallons. When you start reaching 50, that glass needs to get more substantial. My own glass is 5/8ths inch thick on a 105.
A check valve on any line: check valves allow water to flow only one direction and they sound like a real good idea---unless they clog. Because our systems produce a calcium carbonate in such places, and it clogs, do NOT use check valves. A gate valve is fine: those don't clog, and you CAN insert one in your return line to valve down an over-kill return pump to a more moderate flow. THis does not hurt your pump.
Another flood source is a pump turned off, while in a container that sits lower than the other end of the hose in the tank,---or higher, if you happen to have your pump in the tank and have a drain hose going down lower. Pump off, water continues to flow because the water in the hose has set up a siphon suction via gravity. A lot of people get surprised by this one. If this confuses you, diagram it till it makes sense.
Downflow box almost NEVER causes a leak UNLESS you let loose hair algae drift in your system and it clogs your overflow teeth, leaving the return pump sending water up faster than the overflow box can drain it down.
A power failure will NOT overflow a proper sump and overflow box setup, because the sump is filled in a power-off condition, and never filled more than that. A good downflow box is doublewalled, with a high inside wall that LIMITS how far the tank can drain down to about an inch or so. Once that limit is reached, the inner wall serves as a dam. If you've never set up a sump before, get a friend to shout stop at you if you are about to overflow.
And---if you are running ro/di---set a timer! A loud one!
It is also not a bad idea to install a nice loud water alarm in areas where you have a concern.
