All of a sudden I saw, in my main aquarium, that a bit of loose plant part was clinging to the intake tube. Not to the tube itself, to an elbow piece that fits on to hold the prefilter sponge off the wall. It was clinging and waving in current that was pulling it in. That's when I saw the elbow fitting had a crack in it. And I remember when it happened- a while ago I turned the fittings to adjust the angle of the prefilter to the wall, and heard a sharp snap noise. Saw nothing amiss and left it. I don't know how long it's been like this- a week, two? I don't know if it's been compromising the performance of the filter, but several things stand out.
- The nitrates have continued to be higher than norm (35-40 ppm) even though I'm dosing less ferts now.
- There have been small particles loose in the water- I noticed this just yesterday and thought maybe the prefilter was clogged with debris but I didn't want to rinse it yet because I'd just unintentionally rinsed everything the week before- so this friday I'd just done the small sponge filter. Wanted to let the bacteria levels recover after that mini-cycle.
I turned the filter off momentarily to lift out the intake tube and fittings. Removed the elbow pieces and put the prefilter/intake part back on straight off the main tube. So now the prefilter sponge part is resting against the back wall, I don't know how much that reduces its efficiency, but when I put it back on at first the filter wouldn't run. I unplugged/replugged it, nothing. I primed it, nothing. Saw that the water was rushing through overflow, why? I pulled out the main media sponges and gently rinsed the fine one in a bucket of tank water (still here from friday, thank goodness I hadn't watered plants with it yet). Put that back in the filter, plugged it back in, started right up and the current significantly stronger- I saw plants waving around that I hadn't noticed movement from in a while (not good).
- The fish immediately came to play. Barbs were running up and down the wall around the prefilter, flirting and chasing and displaying at each other.
- The tank clouded up with lots of fine debris when I lifted out the intake tube- the one thing I don't like about sponge filters- but to my surprise it cleared up again very quickly. By the time I was done fixing the cracked piece, the tank was nearly clear. And the fishes still darting about looking refreshed. Tells me it's been a problem for a little while, if they feel so relieved and spunky with renewed current. Gah. Why didn't I see it sooner?
Here's the crack: