Hi Sparky,

What kind of pond ar you thinking of creating, hole in the ground, raised or semi-raised?
Do you have a particular budget in mind?
Is there a reason why you want a Tench, you're not likely to see it very much, if ever.
As said above, make it as big as you can, because it's almost guaranteed that you'll wish you made it bigger in future.

Vinegar probably wouldn't be a strong enough acid to have any effect.

Not all slate is inert, depending on where the slate comes from it may alter the Ph.

Try a simple test to find out for sure.
Fill two glasses of water, in one place a largish piece of slate, test them both every couple of days for a week or two.

Water direct from the tap is invariably of a lower Ph than water that's been standing a while, this is because of gases carried in the water mains under pressure being expelled.
The opposite could also be true if the water is low in CO2 from the tap, as it absorbs CO2 from the air to come into equilibrium the PH goes down.

Jay

I suggested it as it's something that the OP could easily get hold of. I wouldn't think it would harm the fish as the fish would no longer be stuck to it, but there is plenty of other stuff that could be used just as effectively.
Those washing up sponges with a green thing stuck to one side would probably interupt flow too much as the sponge is so fine, but one of them flat approx 4 x 6" 1/4" thick coarse sponges would be ideal.

I totally agree that the only real solution is much bigger accomodation.

To prevent the fish being sucked against the filter intake wrap something around it to disperse the flow.
I would use a brand new green scouring pad, it must be brand new and unused as detergents will pollute the tank.
Wrap it around the intake a couple of times so it's nice and thick and secure it loosely in place with elastic bands.
It will catch some of the muck so will need to be removed and rinsed out in old tank water every so often to maintain flow.

Jay

Why not just place all the media from the Fluval into the Eheim filter. Then there'll be need to have two filters in the tank.
There's actually no advantage in running two filters alongside each other for the purpose of moving bacteria from one filter to another. What actually happens is the bacteria eventually ends up split between the two filters, so when you remove a filter you leave the tank short.
When I use a spraybar I place it just below & pointing at the surface.

Jay

Quote:

Violet, The question I asked was not a "thread hijack".
The question regarding qualifications was genuine.

Jaguar made clear exactly what he meant, my concern was that it could be misleading to suggest people are qualified when they are not.

I'm sorry that you feel this is a problem.

Jay

Quote:

Interesting concept, who are the "Qualified Advisors" and what are thier qualifications?

Hi Carol,

Could you give us more details about your tank, it's dimensions and volume if possible.
Could you also tell us about your filtration & how long has the tank been set-up.
Do you have a test kit?, If so could you test the water & post the results.

This information will help us to advise you on the best course of action.

Jay

Ouch, only 20cm x 20cm is incredibly small, it's what is commonly known as a "Death Chamber", which is what we call any tank that is too small to house fish.

Your tank only has a total volume of 8 Ltr, but, will only actually hold 6 or 7 ltrs of useful water volume.
Your fish are really pond fish, as are all single tailed Goldfish, for this reason they need huge tanks & excellent filtration.
For single tailed Goldfish I'd recommend nothing short of 200Ltrs, even whilst they are small, or preferably a pond.

I'm afraid your fish stand little chance of survival & will certainly have health issues in such a small volume of water. Upgrading thier accomodation should be considered a priority.

Sorry it's not better news


Jay