The past 48 hours have been a bit stressful. Obviously I've made a mistake somewhere and I'm hoping that you guys can help me to work out what I've done wrong. Apologies in advance for the long/rambling message, but I'm hoping that the more information I provide, the easier it will be for you to help.
The river tank has been ok, but the more I've watch the way the fish use the environment the more I realised that a few changes needed to be made. I set up the tank with a Fluval FX4, a Superfish airflow 4, and a Jecod DCP 4000 on the river manifold.
To help with the flow direction I decided that all airstones should be moved to the end of the tank with the outflow, and that a larger filter would help create even more flow. The guys at the store asked why I wanted a larger filter, so I told them I wanted it to "blow their bl**dy fins off", without attempting any sort of impression of Micheal Caine, but imagining the fish driving around the tank in little Minis and humming the appropriate theme tune. All staff way too young to understand the phrase used, but I purchased an FX6 thinking it would be an easy replacement.
I did my routine tank maintenence and 10% water change on Sunday morning, and changed the filter. All pipework remained in place, the media & baskets from the FX4 were rinsed in tank water and placed into the FX6. New sponge media and rinsed Alphagrog media were used in the 3rd basket & put into the FX6. Everything was put together with the pipework still in the tank/cabinet, and it was all systems go.
I thought my tank cleaning was fairly decent, but when the FX6 was switched on it seemed to kick up a lot of rubbish into the water, which I guessed was stuff I hadn't been able to reach with the syphon, and which wasn't shifted by the flow of the FX4. Surely that's a good thing, I thought, as at least it is now being filtered. However, I was concerned by the amount of rubbish, so also tried to help by using my other syphon in the tank, which sucks up rubbish but returns the water to the tank rather than removing it (as I'd done a water change less than an hour earlier).
I also cleaned the large sponges on the manifold intakes, hoping that they would also help capture some of the rubbish, even though it is not a particularly fine sponge. At that point I realised that there was no flow on the manifold, so traced back the cables to find that one had come out, so it was off. I connected it and switched it back on again, only to be faced with another plume of crud entering the tank water.
At this point I was very concerned. I chased the largest pieces of crud with the syphon, then decided to do another 10% water change, and put sone fine filter floss on on part of the filter outflow. After doing this I waited an hour or so to see if things started to clear up, but could see that the fish were distressed. Most of them (especially the gobies) were at/near the surface. I did a quick water test, and the results did not indicate an obvious issue (0, 0, <40 as usual), so I guessed it was the amount of rubbish in the water, but was also concerned about oxygen levels because some of the fish were huddled in the flow fron the airstones. I did a 30% water change, and switched the lights off.
Most of the fish seemed to be starting to settle over the hour following the large water change, so I then went to bed. I woke at around 4am, and couldn't get back to sleep, so went to have a look at the tank. I didn;t switch lights on, just used my phone, and could see the outline of several fish in their usual places on the glass, not near the surface, so I went back to bed.
When I got up this morning I checked the tank. Although the water was clearer than yesterday, it still seemed a bit cloudy, the gobies were still near the surface, and I had lost 1 rainbow shiner and 1 assassin snail.
I have done another 30% water change with my usual mix of dechlorinated tap water/RO. The fish still seem a little unsettled, with one of the bulldog plecs, a couple of hillsteam loaches and a couple of gobies still near the flow from the airstones. The rest of the fish and amano shrimp are amonst the wood & stones, with only the most dominant plec, 2 panda garras and the rainbow shiners out in the open.
I'm going to put some fine filter floss on one of the filter outputs to help with fine particles. I'm also going to put some carbon in the tank as well. I haven't used any plant fertiliser or carbon in the tank for 3 days, and the dechlorinator I'm using is the Aquacare tap water conditioner. Water temperture is 20C, and I'm keeping the lighting relatively low (only 1 set of lights on, rather than all 3).
Apart from continuing with daily water changes, what else can I do?
Is there anything else that I can/should be testing for at this point?
I'm guessing that all the problems have been due to the particles in the water, rather than chemicals/toxins, but any suggestions and/or advice are very welcome.