Can't Get Phosphate Levels Down

[NICKM]

I have a 180 litre community tank.
Well stocked, but not overstocked.
No plants (some bogwood).
A powerful external Eheim professional ii filter.
An internal Jewel filter too.
I feed the fish on (about) 4 frozen cubes of assorted food daily (max, often only 2).
Plus maybe a couple of plec wafers for my 25cm plec.
Ph 6.8
Gh 5
 
I cannot get the phosphate level down at all.
In the past month I have used
100ml of JBL PhosEx Rapid
Then, when this didn't do much.
250 ml of Rowa phos in both filters.
Also weekly 20 litre water change.
The phosphate level is still above 5.
 
Has anyone any idea what I could do to get this down?
I'd really like to get some water that doesn't encourage algae.
 
Thanks
 
Nick
Nottingham UK

 

[Lolly123]

How many fish do you have in the aquarium?

Four cubes of food sounds like a hell of a lot of food to me, I feed nowhere near that much and sometimes I even skip a day of feeding on the odd occasion. It sounds like you're putting too much food in there. I believe some foods can contain phosphate, I think it's a preservative in some flake food and i believe frozen food contains phosphates too. It might be worth checking the amount of phosphate that's in the food you are feeding.

20L water change in my opinion is not enough, if you're not performing gravels vacs and there is excess food, detritus etc rotting away that is most certainly not going to do anything for your water quality. I perform about a 35-40% water change weekly and gravel vacs are regular with that, you're also gonna need to move the wood around and suck out any rubbish that has settled underneath it.

Just for information purpose you could always check your water supply for amounts of phosphate.

But to me it sounds as if you are over feeding and not doing enough tank maintenance. Increase water changes, cut down on food, and give the substrate a good vac to remove excess food, fish waste etc.

If you haven't done so already it may be worth giving your filter a gentle clean in old tank water.

 

[NICKM]

There's about 35 fish (between 3 - 7 cm) plus the large plec.
 
I'll do a bit more vigorous hoovering and up the water change volume as well as cutting down on food and see what happens, will post again in a couple of weeks with update.
 
tested tapwater - about 1.5
 
Thanks.
 
Nick


As an aside - my ph keeps wanting to drop and I am always having to bring it up (not with a phosphate buffer).
Might this be linked?
Nick

 

[Lolly123]

What does your PH keep dropping to?

If you are having problems with your PH, I would suggest testing KH - the carbonate hardness, which buffers your water and keeps PH stable. And also testing GH - the general hardness of the water. You need to know these as these are the main factors in keeping a stable PH which resist large swings and changes. You can find decent liquid tests by API for both KH and GH.

Also note that bog wood can reduce your PH and if the above parameters are measuring on the low side this may be further aiding the PH drops that you are experiencing.

PH swings can be very detrimental to your fish, and many people approach this cautiously as swinging PH's are far more dangerous than a stable PH that may sit outside of your inhabitants 'ideal' range.

I think for anyone to advise you further on this, you need to get those parameters and post them.

I have never suffered with PH swings as I live in a hard water area, luckily enough. Someone else may pick up on this thread and guide you further when you have some more info to give.

Thanks.