When should I do water changes

Hi,

I'm new to this and I need some advice...

I have a 25G tank with an Aqua-200 filter. I have 6 rasbora Brilliant (redtailed), 3 tetra neon (blue), 2 tetra black widow , 3 Head-light, tail light and 1 snail. I have 2 living plants.

I added them slowly, 2-3 at a time. (3 rasbora helped for the original cycling of the tank)

The tank as been stable for 3 weeks now, all my test on the water are good (0 amoniac,Ph 7, 0 Nitite, traces of nitrate)

Should I do partial water changes in those condition? Should I vacum the gravel as I don't see nitrate (my plants need some, right?)?

What else can I do for my aquarium?

Thanks,

For reference, you have about 8' of fish-load in a 25g tank. Unless you are feeding them 4 or 5 times a day, that's a pretty light fish load. Whenever you do a water change, you should just get into the habit of gravel-vacuuming. You want to remove all the detritus before it dissolves into the water. Besides nitrates, there is a lot of other stuff in aquarium water which you cannot measure with your test kit, and some of it you don't want building up. There would be nothing wrong with doing a weekly 20% water change, and if you miss a week (or 2), no

Thanks, I didn't know there would be other toxics things in the water... Is there any way to test for those? Well anyway, I'll start doing a weekly water change with gravel vacuum (especially inside the caves (small plasctics ones)....)

BTW, you might have missed some of my fishes in your count (I do that sometimes in my daily fish count... some are quite good at hiding... in the caves, I figure)

3 of my rasbora are 1,5' (the others are 1' (7.5', my black widows are 1.5' too (3' My Head-Tail light are a little over 1' (3+' my neon are small (let say 2' total) and 1 snail (count for what? 0'

(I feed 3 time a day, 3 minutes each time.. Is that enought?)

total : 15' on a maximum of 25' (right?) which gives me some room for growth and addition (a bottom-feeder maybe... suggestion? (a plec thingy (orange with stripe, I saw at the LFS... would that be a good one?)))

There are many instruments used for monitoring elements in water, but none that would really be needed for your application. It's not necessary to know the chemical make-up, but to understand that all non-living organic matter decomposes (fish food, plants, fish poop etc), and in water, it dissolves and mostly stays in the water, making the water 'thicker' (increasing the osmotic pressure across the fish's gill membranes). You might hear the term dissolved organic compounds (DOCs) which can be somewhat measured by conductivity, and there are many others, some we cannot measure without the facilities of a very good lab, some we cannot measure at all.

In terms of fishload, it's really the amount of food they eat which determines the fishload (the food starts the nitrogen cycle, which is typically what we call 'fish-load', referencing the biological requirements, rather than respiration requirements). Most of your pets are not herbivores, so the food is the fish food you drop in. Tetras have a very small biomass, so you can't really count a 2' tetra as 2' of fishload. I get about 7' and I added another inch for your snail, but that might be conservative as many snails will eat algae and plants all day long, so they could account for a large part of the fishload.

You have lots of room left but research your pleco well. Many are strict vegetarians (so you might need to augment their diet), some grow quite large, and because they are always eating, they have a high fish-load.

Here is some more info on stocking guidelines, taking into consideration a lot more than inches of fish.

Twice a day would be fine and you could skip one day a week.

grin...........

Thanks... If the pleco I was intending to buy is not a good one, what kind of bottom feeder would you suggest?

That all for now, as I have to do water-change/Gravel vacum (and find two missing neon, gone for 2 days now...)

By the way, great site you have, lots of informations... And you have quite an impressive background.... we can say that you are a professionnal Hobyist...