Suction cup frustration...

Today, I've had it! I've dealt with the problem for about 20 years now, but no more! What do you folks do to ensure a good hold using suction cups for canister filters, or submersible heaters?

Mine always seem to slip, while still sticking to the glass. I am also getting to the point where glass cleaning around these things becomes a nightmare.

Normally, I would remove the siphon, clean the glass, and then put it back. My new 125g tank makes it difficult, the way the glass cover and light are.

Even when I remove the suction cups, clean the glass, and then the cups surface (suction side), I still find they hold fine, but they slide around.

Any suggestions?

Perfect timing for your question as I too was pretty cranky when I got up this morning and found my internal filter sitting almost on the bottom AGAIN, held up only by the power cord. Ditto with heaters and I've only been in the hobby a bit over a year. How have you put up with it for 20 years? You must have way more patience than me.

I set my heaters back up in the tanks a couple of days ago ready for winter and came to the tank with the internal filter - I'm concerned the heater could end up against the filter and melt it or something

Plan A : use new suction cups (old ones get too hard and basically useless). Plan B : apply cups to only very clean glass (preferably clean dry glass with a bit of spit inside the cup). Plan C : avoid dependence on the suction cups (outside using a combination of the canopy glass slider or cutout to push the pipe into place, and inside, using rocks/wood/ty-raps to hold it in place).

Also, the suction cups work best if they are holding something in place, which would normally not move anyways. If there is much pressure on the cups, they will usually let go eventually.

I'm looking forward to reading what inventive ways folks have, to work around this nuisance.

Put a little petrolium jelly on the cup........... Frank

I have pretty much given up on suction cups. I have glass sliding panels on my tank. I hold the floating thermometer in place with a bit of clear fishing line tucked under the edge of the glass slider channel. The heater is placed in a cutout opening just large enough for the glass tube to slip through, so it just dangles into the tank. I have an Eheim surface skimmer attached to my canister that still keeps sliding down. Too bad there isn't a plastic clamp available to hold it in place at the top edge of the tank.

Could always plumb everything under the tank (filter, heater, Uv, etc ...). Only thing in the tank are the intake and the return hoses.

My cure after going through the same problems was on a new tank setup, preinstall the cups with silicon. For existing tanks, I would coat the cup with cooking oil. Take a cue tip, and dip it in the oil, a very light wipe on the cup and put it in the tank. The cup will still eventually let go, but months down the road, not on a weekly or daily basis. For permanent mounting I go with silicon

The cooking oil didn't work for me I just tried it and the filter was back near the bottom of the tank before I even sat down. I've pulled it up again to give it another go.

And it has been up ever since

It seems like cooking oil or petroleum jelly would not be too good for the aquarium water. You can avoid the heater problem by using the fully submersible types and putting them on the bottom of the aquarium. As for all those other suction cup things, they're best at demonstrating the power of gravity.