Impeller Sorted But,add Two Mistakes

You are not going to like this but I would put the grill back on. Filter floss isn't very strong, it does tend to fall to bits, and if it's left without the grill for any length of time I would be worried that some bits might make their way into the impeller well.

As for the impeller itself, the manual wasn't very informative last time I looked (for your other thread) but the diagrams suggested the impeller shaft should have a rubber cap on each end which, if it anything like my aquaball and biopower filters, should mean the white shaft is held rigid when the impeller cover is fitted. Or do they mean to test the impeller is moving freely before you fit the cover?
But if the water is flowing, the impeller must be going round.

Sorry just read the other posts but nothing seems very definitive.? Or am I misreading them?

Hi Sue 
 thanks very much for your advice and info. I replaced the grill. After some actual thought  I did it in situ,
so not as onerous as I'd imagined. Plus after re reading the manual lots of times noticed it advised checking the impeller by plugging  the unit in, before refitting the whole filter. So all ok.
Re pH you'd advised me years ago to get the info from  the waterboard site. I keep a fish file and had printed off your comments and the  water quality report from Thames water.(2009)this says pH 7.4. I had checked and recorded it myself last year, the same, pH 7.4  Double checked by testing the tap water today now 7.8
Re the KH and GH you'd commented in 2009 after checking the water quality report for Thames yourself that Thames doesn't have alkalinity /KH listed.
It may have now and I did try to quickly access an up to date WQR sometime ago without success but will have a concerted try again. I can buy a KH tester if need be ( which you'd suggested) but you concluded in ŷour comments that my water is hard.
Can I ask? is the amount of  difference between the tap and tank pH usual/ normal ?
Thanks again for all your help.
Best wishes Rosie

Freshly run tapwater is often different from tank water - and from tap water that has been allowed to stand for 24 hours. If you haven't already done it, can I suggest you leave a glass of water to stand till tomorrow then test the pH of that water.
When tap water is hard there is a risk of limescale building up in the water mains. Water companies often pump carbon dioxide into the mains water; this dissolves making the water more acidic which slows down the rate of limescale depositing. When you leave a glass of water to stand, this carbon dioxide gasses out of the water - it is the same as leaving a glass of lemonade out all night and finding it gone flat in the morning, just a lot less gas. As carbon dioxide leaves the water it becomes less acidic and the pH goes up.

If the stood-overnight pH is still lower than the tank pH, think about your tank decor and gravel/sand. Do you have any limestone, coral or shells in the tank? Is your substrate just plain ordinary gravel or sand, or one of the fancier types which could be made from limestone etc? These dissolve very slowly increasing pH and GH and KH.


The hardness of the water is more important for fish than PH. They can cope with a pH that is not quite right better than with hardness that is not quite right. I have moderately soft water but a pH of 7.5-ish. I can keep fish that like soft water and a low pH better than fish that like hard water and a high pH.
You have hard water and a high pH (south east England is known for its hard water). Unless you are willing to use RO water at every water change to dilute your hardness, you would be better sticking to hard water fish.

There are two reliable sites.

http://www.fishbase.org/search.php gives water requirements but little else. However it actually intended for scientists so the info is reliable. I have found a hitch with the site recently. When you search you get a list and you click on the fish name on the list. Sometimes it won't go to the profile. If this happens, go to google and type in the fish name followed by fishbase. That usually works for me.

http://www.seriouslyfish.com/knowledge-base/ This site gives more info on each species.

Just to add about Fishbase - for anyone else who goes there as well -

There are several fishbases - .org, .us, .de and so on. If one doesn't work properly, try another. There's a list across the top of the page.

Experimenting this morning on .org, typing in the latin name in any of the boxes didn't work. Typing in the common name did work.
.us won't work at all.
.de worked fine for me.

I've found this on previous occasions, one day one of them won't work, then try again a few weeks later and it's fine.


And you can't use the back button on your device to get back to the search page. You need to use the 'back to search' at the bottom left of each profile.