I have a 100 gallon tank - fully cycled 18 months ago. Water quality is spot 
on. It houses 1 very large plec, 2 large silver sharks, 2 moonlight gouramis,
 5 clown loach, 5 pakistani loach, 1 tiger barb and a few guppies and 
platies. I've 2 questions, please. Firstly, is it usual to have to clean the 
filters weekly. I have 3 fluval 4s in there and if I don't clean them weekly 
they get gunged up and blocked. Am I overfeeding? - Plec gets a 3" chunk of 
cucumber every morning for breakfast. Secondly, my ph level was always 
dropping because I have a lot of bogwood in there, so I've added acouple of 
cowries to act as buffers. The ph level is now constant, but I've noticed 
that whereas before the guppies used to breed and the platies didn't the 
situation has reversed. The guppies have stopped breeding and I'm losing 
them one by one, but now the platies have begun to breed profusely. Ph is 
about neutral now, so what can I do to keep both guppies and platies happy?

"Anne Reece"  wrote in message 
news:adbeaad6095e478c8bcbde6972796f3f@newspe.com...
>I have a 100 gallon tank - fully cycled 18 months ago. Water quality is 
>spot
> on. It houses 1 very large plec, 2 large silver sharks, 2 moonlight 
> gouramis,
> 5 clown loach, 5 pakistani loach, 1 tiger barb and a few guppies and
> platies. I've 2 questions, please. Firstly, is it usual to have to clean 
> the
> filters weekly. I have 3 fluval 4s in there and if I don't clean them 
> weekly
> they get gunged up and blocked. Am I overfeeding? - Plec gets a 3" chunk 
> of
> cucumber every morning for breakfast.

Isn't a Fluval4 an internal canister?  I think you need some 'real' filters 
;~), for the very reason you have indicated.

> Secondly, my ph level was always
> dropping because I have a lot of bogwood in there, so I've added acouple 
> of
> cowries to act as buffers. The ph level is now constant, but I've noticed
> that whereas before the guppies used to breed and the platies didn't the
> situation has reversed. The guppies have stopped breeding and I'm losing
> them one by one, but now the platies have begun to breed profusely. Ph is
> about neutral now, so what can I do to keep both guppies and platies 
> happy?

I don't know what a 'cowries' is, so I'll presume it has calcium carbonates 
to boost your buffer.  A possibility is that your driftwood is having less 
effect than you thought and it's other organic matter causing the problem. 
Filters clogging too fast is also a clue.  What is the condition of the 
substrate?  Gravel vacuuming frequently?  Water change routine?  Live plants 
in there?  NO3 levels?

If you have an excess of organic matter decaying (evidenced by a low buffer 
and your pH dropping), then your water may also be getting too 'thick' (high 
in dissolved organic carbons or DOCs).  Adding carbonates (cowries?) shores 
up the exhausted buffer, but does nothing to help the high DOC level.  One 
of the symptoms of high DOCs is certain species of fish getting sickly or 
changing their behaviour.

I have a tank with M. argenteus and they are somewhat sensitive to high 
DOCs.  Their nostrils go white if I miss one week of water changes.  If I 
miss a few more weeks, they will go dark and die.  Meanwhile, all the usual 
water parameters are normal, pH, gH, kH same as tap, NO3 about 20ppm and 
zero NH3/4 and zero NO2.  It's the water getting too 'thick'.  I think a TDS 
measurement (total dissolved solids) - gH = DOCs but don't quote me.  I'm 
not currently measuring anything.  Currently I only need to look at the fish 
to know.
-- 
www.NetMax.tk