too large of a waterchange.

[jong101]

So, i have been thinking of doing a large water change, my parameters have been getting better but i have been consistently at around 20 on my nitrates. the phosban reactor cut down my phosphates, and everything is great. i cut down feeding and such which has worked wonders.the cheato is also gowing at massive rates.... So i finally bought my own ro/di from filter guyz instead of having to constintly going to my lfs for water. so now that i have my own recourses for water i was thinking of doing a 30-50% water change to cut the nitrates once and for all. From what i have read there is no danger in a large water change, any suggestions or reasons i shouldnt do one that large all at once??? any info would be great

[seagirl]

when i upgraded tanks last time, i used 100% new ro/di water(my old tank had tap water). i just made sure to acclimate the residents to the new water and everything made it ok.

[trigger111]

It can be very dangerous if not done right. If you do it make sure PH, temp, SG, Cal, and Alk are all very very close to the levels in the main tank. You can get away with having the parameters a little off with smaller water changes without it making a huge impact. However, with large water changes even small variations in the parameters between the new and old water can lead to not a good outcome. It can be done you just have to be a bit more carful than a regular water chage about it.

[jong101]

ok, so i should just make sure the parameters are relatively similar, i figured that much. I could also change a large amount of water over the course of a few weeks, maybe that would be an over all safer thing to do.

[seapug]

I found this article informative and helpful:

http://www.wetwebmedia.com/scottsh2ochgart.htm

[kevin2000]

A large water change is fine ... just make sure you use "aged" SW where the temp, PH and salinity are OK.

[jong101]

yea i thought fresh mixed water needed at least 24hrs to "age"

[papagimp]

Also keep in mind that removing large amounts of water will also remove large amounts of bacteria in the water column.

And I wouldn't expect this to rid you of nitrates "once and for all". That's only going to happen if you take proper care of the tank over time. There are no "quick fixes" in this hobby. Once the cheato grows sufficiently, you should notice nitrates going by by though.

[kevin2000]

Originally posted by papagimp
Also keep in mind that removing large amounts of water will also remove large amounts of bacteria in the water column.

Thats a common misperception ... beneficial bacteria don't reside in the water column (to any significant extent) .. they reside in the substrate, live rock, and even on the walls of the tank.

[jthao]

imo, multiple smaller water change is a lot better than 1 big water change. instead of a big water change every month, I'd rather do a small water change every week. in your case, if you want to eventually have all rodi water in your tank, just do a few smaller water change over a period of 2 months or so. I'd do every week for 2 months or so. good luck

[kevin2000]

Originally posted by jong101
yea i thought fresh mixed water needed at least 24hrs to "age"

Depends on the salt your using and even whether your using RO water ... but 24 hrs will certainly help insure that the salt has dissolved, the temp is right, water has properly aerated to stabilize PH. Using a small ph when mixing up a batch of SW will help insure that the salt is dissolved and the water is aerated.

[jong101]

i am aware that there is no "quick fix" but bottom line is that the ro water from my lfs tested at 1ppm of tds, so me switching over to 0 is gonna be beneficial. I just want to be able to get the nitrates down then maintain that with weekly/bi-weekly water changes(from what i understand ideally 30-50% a month). And i had read a while back as kevin2000 had stated little if any beneficial bacteria resides in the water column, so that said doing an initial large water change ( granted the levels match) as a jump start to keeping my nitrates down would not be horrible.

[wooden_reefer]

In some setups it is convenient to remove a lot of water at once but add back over the course of a couple of days.

Not always possible.

You do not get rid of nitrate "once and for all". Nitrate keeps generating. Most tanks have denitrification activity by which nitrate goes back to nitrogen gas.

[AmosUSA]

does anybody use natural sea water?

[szwab]

you'll reduce a larger % of your nitrates and whatever else with the larger water change compared to smaller ones. that can be mathmatically proven. Just make sure that your params are very close to you tanks water and you should be fine.

[jong101]

thanks for all the input guyz