I put a sponge pre-filter on one of my Aquaclears last week and, while it's been doing a great job (I no longer get the "rising basket effect" from a clogged internal sponge), it itself clogs up within around a week and has to be taken out for a cleaning (such as last night), lest it choke off the water flow. It's annoying enough that I'm considering removing it and looking for other options.
Look into a replacement sponge filter, the taller cylindrical type, there are different size fittings in the nice quality ones, they are very much larger ( could be a negative, though cleaning every few days would be a negative as well). If you aren't trying to keep fry or cherry shrimp out of the filter you can check out a more coarse foam pond prefilter sponge as a possibility too.
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The Amazonia balls are drying out in the bag, now that I have it opened to the air. Firmer. The email I received said the soil is normal, mouldy smell and moist mud...is NORMAL. Amazon asked if my question had been resolved and of course NO. I added my 2 questions again.
They original email I received a useful bit of info about how the product will produce/leach ammonia for weeks. Thankfully I already know that and woudln't have killed off my little aqua critters. They went on and on about it with links. But didn't answer if a mouldy smell was normal or the mush silt balls.
I told them if that IS normal they can take it back. Or if they can't answer my questions they can take it back. And that I was disappointed and would share this experience. So we will see what they do about it. MY opinion would be that they replace the bag after smelling it and making sure it isn't mouldy smelling. Earthy and mouldy are two different smells. I wouldn't put that in my PRL Shrimp tank.
So far didn't even get it into water yet/ start leaching the ammonia out, in case they want to take it back. So now will be off schedule about a week or 2 by the time it is all over with. In the big scheme of things, shouldn't let it bother me but I am irritated. Mostly because I feel like I took a leap out to the edge to buy such an expensive substrate, when the other stuff would have been okay. This is from the U.S. sales arm of ADA. 2 more days of waiting for an email.