co2 solenoid problem

[mvh pets]

hi!

i recently got a new co2 set for my 1000 litre (240 gallon) aquarium. i addend a external solenoid to it to automate it, however, whenever i switch to solenoid off, the tubing behind it starts to expand a lot, kind of like a balloon about to burst( this happens within 1.5 minutes), is this normal, as i am scared to turn the valve off for more than a few minutes( which is kind of a waste). if it is not normal, is it possible to use the co2 without the solenoid ( maybe by running at a very low bubble rate  for the whole day) 

[DavidR]

That seems odd indeed. Hard to tell for sure without pictures what is going on. I'd buy a quality CO2 system with dual stage regulator, it really isn't something to mess around with on the cheap. Could lead to gassing your fish.

Running a small amount of CO2 all day isn't the same as running the proper amount during the photosynthesis period for plants. You need to get the amount right during that period and really isn't needed the rest of the time. 

[gardenman]

On 9/7/2021 at 6:44 AM, mvh pets said:

hi!

i recently got a new co2 set for my 1000 litre (240 gallon) aquarium. i addend a external solenoid to it to automate it, however, whenever i switch to solenoid off, the tubing behind it starts to expand a lot, kind of like a balloon about to burst( this happens within 1.5 minutes), is this normal, as i am scared to turn the valve off for more than a few minutes( which is kind of a waste). if it is not normal, is it possible to use the co2 without the solenoid ( maybe by running at a very low bubble rate  for the whole day) 

It sounds like the tubing you're using isn't rated for the pressure it's experiencing. The solenoid is simply an automated on/off valve that gets triggered by electricity. When the valve is open and CO2 is flowing there's less back pressure on the tubing as the CO2 has someplace to go. (Into the aquarium.) When the solenoid closes, there's no place for the pressure to go so the tubing is expanding due to the increased pressure. There are two real options. One is to replace the tubing with something stronger rated for the pressure it's getting. Option two is to reduce the pressure. Shutting the valve on the CO2 tank itself down more can reduce the pressure in the line and prevent the hose from potentially bursting. A wide open valve on the tank will let a virtual river of CO2 flow from the CO2 tank while shutting the valve down more can reduce it to more of a trickle of CO2. Your tubing should be able to handle a trickle of CO2 better than a river of CO2. 

[Tihshho]

On 9/7/2021 at 6:44 AM, mvh pets said:

whenever i switch to solenoid off, the tubing behind it starts to expand a lot, kind of like a balloon about to burst

The solenoid you bought looks to be an inline unit to be used for low pressure systems and not compressed. If you're running a compressed system with a CO2 canister (not DIY with sugar yeast, or a dual bottle with baking soda and citric acid) you're going to be running at too high of pressures for this setup. The inline couplers look to be setup for airline tubing, at the very least you should probably be running high pressure pneumatic tubing. The best overall solution is to have an inline solenoid build into your regulator, from there everything will be hard lined and be able to withstand the pressures being applied.