Water changes!

Seems to be a lot of interest in water changes - a how much, how often etc. I change 30% of the water once a week because I dont have time. I would like to change it twice, but I've gotta eat! Now heres the result from a little experiment we did back at the aquaculture center at Uni of Tas in 1992. We we looking at differing growth rates compared to water quality. The fish we used were discus and dwarf gouramis. The filtration in one group of tanks was a sponge filter, another group had a trickle system, one had an 'all singing and dancing system' consisting of trickle, nitratereductor,sulphur,carbonate, calcium reactors and another which I cant remember. The last system was getting a 50% water change each day. The results were interesting. The fish with the highest growth rates were from the tanks with the all-singing -and-dancing filters, next was the water change tank, followed by the sponge then trickle (I think). The lecturers do this experiment to show the importance of filtration. Now we wondered why this could be so. Upon examination of the fish (histo-toxicological), it was found that the fish with the highest growth rates given the same food had less blood cortisol levels. When a fish gets stressed, it produces cortisol which lowers the immune system, reduces resistance to infections/pathogens and ultimately inhibits successful spawning in some cases. The reason behind the higher stress levels in the water changed tanks WAS the water changing (physically disturbing them) or buildups of toxic metabolites (remember that biological filtration only removes nitrogen bases metabolites and converts it to nitrate). Also these fish were not used to being disturbed with water changes like mine are, but still - food for thought. Wild stuff, like Heckels wont tolerate any disturbances during spawing season, or they just wont breed!

So the results are interesting. I just thought I'de share this with you. Also, so only way I've bred Heckels out of the pond was by using a stable system with all the bell and wistles in the filtration end. Large water volume (as we fish disease guys say - 'dilution is the solution to polution!')

Someone answered one of the threads in this forum with ' there are too many vaiables with water changes' ie whos right or wrong about frequency of the changes. Dead right - a large tank with low biostock density needs less changes. More intensive systems EG fry growout are gonna need more changes. It really comes down to stocking density. If I walk into my fish shed and see some discus looking a bit dark or not eating with enough vigour or flighty, then I give them a water change. As most of you will know, each of your discus have their own personalitys and traits. I know each of my 20 or so adult brooders by name and personality and I know when somethings not right. Thats when I do my changes.

If anyone wants to try out some of these hi tech filtration systems, have a look at them on Proteus' APW site. They can be expensive but are well worth it (and yes - you'll still have to do water changes, but not as often) Food for thought

Squid

Good advice Squid theres no right or wrong way and i agree with knowing a fishes personality. Some of mine when breeding will allow me to do water changes, others just by their movements and temperment wont allow it. I do a 50% water change for my tanks per week only due to the fact it "works for me" and if i had the time would do more. The fish are happy and im happy, but some other people may have to do more each week dependign on local water conditions, stocking levels etc, too many individual variables for each individual case.

What's the link?

Thanks

i do 10% daily on my discus tanks and 40% every 3-4 days on my cichlid tank.....ok ok its sounds like a lot of water changes but heres whats in the tank...
12-14blue dolphins 12-18cm
18 E'yellows 4-12cm
5cuckoos 10-12cm+
3clown laoches 7-8cm
1 pictus 12cm
12-13BN 4-8cm
6Eblues 4-6cm
1 3spot 4cm
and the tank is only a 4x15x18 :oops: they will be going into a 8x2x2 ONCE the insurince coupony(SPELLING) hurrys up with our floors

very informative squid

This would make a good sticky I think anybody else agree?

Very informative Squid!

Indeed it is Sammi, and deserves to be a sticky.

Thanks Squid. We love information like this.

Yep it was interesting, the only problem I have now is I dont think I'm changing my water enough.......so I think I may just have to give up sleeping at night now as well as maintain 50 or so tanks. :roll:

Thanks for the information Tony and an excellent sticky!

I like the idea of the "flow through" tank system.

It creates an environment where filtration is not needed as there is constantly fresh water within the tank and there is none of the water change shock associated with doing water changes greater than %20.

I have tried and tested this "flow through" tank method and found I achieved healthier fish and a %10+ better growth than conventional methods.

Of course having this style tank set up is costly and generally not practical for
the domestic fish keeper and or breeder.

Dead right Ben - very expensive way to go about it, but when you consider what a batch of F1 Tefe Greens will sell for!! Another problem is it takes up a fair bit of room. Thanks for all the comments too guys!

Squid