I have a 29 gallon tank with an Ehiem 2215. I have been doing water changes with just a 5 gallon bucket, then refilling with a 1 gallon pitcher (to reduce plants getting tangled up). Obviously, this takes a bunch of time.
I was wondering if there is anyway I could plumb this into my existing tubing to my canister and use a fountain pump to fill it up. I do not want it set up all the time, first and foremost.
I was thinking about doing 1 of 2 things. The first would be to put a "T" into my line and put a hose on. I would use an Ehiem quick disconnect (or similar) on the "T" so that I can open and close it up. I would also do the same at the end of the pump. That way I could easily take it off and put it back on. I would do it on the outflow side so that my pump doesn't have to compete with gravity, shutting off the existing quick disconnects I have off before and after the filter.
The second way would be very similar with the exception that I wouldn't use a "T" in my line. I would mearly hook it up to the existing quick disconnect on the outflow, put a quick disconnect from the inflow, and just hook it up to my existing connections. Basically the same idea but simplified. The problem with this, I can't easily drain my tank this way (unless I hook it up to the inflow side, then disconnect, hook it back up to my inflow).
These are the problems I can think about right now:
First, once I get past the top of the spray bar, it may back siphon into the bucket that the fountain pump would be in. I am not all that worried about that. I could only siphon to as low as my spray bar so no risk of overflowing the bucket my pump would be in.
If it doesn't back siphon, it could overflow my tank if I am not careful. Again, not to worried as it's not supposed to be automatic. Pretty easy to keep track of how much water goes out so I know this won't happen with some basic common sense.
The 3rd thing is the durability of these quick disconnects. I have broken the handle on the valve for one (after about 3 years however). But, I could have a problem if one is stuck open, especially if I do it the second way. They also leak from time to time if I don't lube the O ring. No big deal once every year but using these things every week, they may not hold up.
Here is a quick caveman painting to show you what I mean: