Ciano40 Filter

Having purchased a new tank (aqua 20) with a ciano40 filter included, I set it up for my betta fish. It looks great, functions well enough given the price (£40) and has been fine apart from one minor user error with the filter.

However, speaking of the filter, it is quite an aggressive flow rate despite having a fancy “spray bar” which isn’t great given it’s for a betta fish and it’s so powerful it’s moving the sand around at the bottom of the tank! Is there any way to adjust the flow rate??

I don't know those filters, but I do have a lot of experience with dealing with flow rate because of my axolotls.
If there isn't a switch/dial/lever on the filter to alter flow rate there are still a few things that you can do to help reduce the flow:
Increase the width of the holes in the spray bar (scissors, screwdriver, whatever, but please be careful)
Point the spray bar towards the side of the tank rather than into the middle of the tank
Push the filter lower into the water and point the spay bar slightly upwards so most of the flow is aimed at the surface of the water
Wrap spray bar on a thin layer of coarse filter media or clean fabric (muslin cloth or similar) to baffle the flow

Let us know how you get on.

Best of luck.

My thoughts are that tomorrow I’ll go back to the shop and ask to exchange the filter given that it was marketed for Bettas and so should not be so harsh. If that fails, are there any relatively cheap alternatives I could get?

This issue is very much on my radar as I have some elderly fish, who have been struggling with the filter in the main tank, and some have been transferred to my small 17L hospital/quarantine tank.

Some options are:
* Eheim Mini Up (25-30L) ;
* Dennerle Nano Corner filter (10-40L);
* JBL Cristal Profi greenline Matten filter;
* Fluval Mini (up to 45L);
* Aquael Fan Mikro Plus or Mini Plus.

As the filter which came with the 17L tank is very temperamental, I bought an Eheim Pick-Up 45 (larger than the one I mention above) which was certainly absolutely fine for the cardinal tetras during their month's quarantine. I had read very favourable reviews about the Dennerle filter and in fact made an impulse purchase the other day (Pro-Shrimp had sold out and I got it via Aquarium Gardens) to see if it might have an even gentler flow as I expect the elderly fish may be living in the hospital tank long-term - however, I haven't set it up yet.