Importance of water changes...


In Memoriam
I'm not gonna lie...Since I've had my 75 gallon SPS tank setup I've been VERRYYY lazy when it comes to water changes. Its been almost a year and i've done maybe...4? But with the growth and everything i've had in the tank it just hasn't really seemed that critical to me..I've got 50x turnover 2x250 14000k MH, dose B-Ionic 2 part daily...which replaces Calc/alk/magnesium, other than some trace elements what am I really missing out on on the water changes, I skim heavily and pull out muchos gunk a week.


Active member
I did the whole blow off water change thing.. ya you won't see a difference for the a bit, then one day..BLAMO you realize everything is out of wack and you spend the next 3 months trying to fix things.. long term.. it's a bad idea.

WC replace other "essential" trace elements, as well as physically remove waste from your water. Alot of times you'll think nothing is wrong as n, p and getting sucked up by other means but once those means are exhausted you'll be battling water quality issues for some time.


New member
"mal"-nutrient export and element replacement

how about you pee and poop in 75g of water and have to swim in it all of the time? :)


Premium Member
I'd like to stress the "mal-element" thing. There are things that aren't removed by carbon and skimming that eventually build up. It may take a while, but trust me, you'll have problems. I have gone for much longer without water changes (years) and a problem results eventually. Why not just get them over with and prevent problems in the future?


Master of my domain
i can see some cyano so im guessing you have high nutrients prolly from neglecting to do water changes.


Master of my domain
<a href=showthread.php?s=&postid=12835713#post12835713 target=_blank>Originally posted</a> by Amphiprion
Why not just get them over with and prevent problems in the future?

<a href=showthread.php?s=&postid=12835713#post12835713 target=_blank>Originally posted</a> by joker577
I've been VERRYYY lazy when it comes to water changes


Formally registered membe
an ionic imbalance of chlorides or sulfides would be a reason to do water changes.
I had a customer that used to brag that he had his tank for over a year and has never done a WG. I told him don't be surprised if one day you come home to...............well...........a dead tank. Needless to say 2 months later he had a minor 2 hour power outage and the entire tank crashed. A clean tank can handle adversity much more then a dirty one. IMO a dirty tank is a ticking time bomb waiting to explode!!

It also appears you have a very light bioload so you may be able to go without a WG longer then most people but one day the **** will hit the fan and you won't be happy


New member
Mikeee welll friggin said man!

This hobby is not for lazy people

It takes some dedicated time to clean and take care of these creatures, no matter how much you try to think you can skimp, the tank will always tell you whats up.

<a href=showthread.php?s=&postid=12837170#post12837170 target=_blank>Originally posted</a> by joker577
Wasn't asking for criticism, only opinion on water changes

Must be new to RC huh;) Criticism is in abundance here my friend..............sometimes good most of the time not:lol: :lol: Don't ever take it personal unless they make it


New member
Sorry. I too used to think why do so many WC's? once every 2-3 months is fine! while this may work for some with a fully automated system.. its like some people say.. a ticking time bomb ready to go. As long as your lucky.. you may get by doing a WC every 2-3 months with a fully automated system but when you luck runs out everything will all come crashing down..and then you question.. hmm why?? Ever since i had started doing 10% weekly WC i have notice a BIG difference..everything just does better both corals and fish. And whats so hard about changing out 10% weekly.. for the average lets say 100g its only 10g. I use to change out a larger amount every month or so about 30-40% and i could see the stress it wont put on the corals and yes IMO i believe its important to do water changes (less, but more often).


New member
Lots of people drive in their car without wearing a seatbelt, or their motorcycle without a helmet. They're fine unless something goes wrong, then they're at the mercy of circumstances.

Water changes are your seatbelt or helmet.


New member
You say that your tank has been up for a year??? how long have all your corals been in there? I will reserve judgement, but if your answer is that the corals have been there a year, the answer to you question on water changes, may answer itself.


the jewish superman
<a href=showthread.php?s=&postid=12838135#post12838135 target=_blank>Originally posted</a> by mcliffy2
You say that your tank has been up for a year??? how long have all your corals been in there? I will reserve judgement, but if your answer is that the corals have been there a year, the answer to you question on water changes, may answer itself.

i agree.


you cant buy blue fingers
Premium Member
heres a tip:
Go to the tank of the month section of reefkeeping magazine,or any other fine reefkeeping publication/messageboard and see how many of their stunning tanks dont do regular water changes, you will find very few, then compare your tank to theirs, read some of randys articles on water changes, start doing regular water changes as part of a good routine for sps.

you can get away with less changes for an anemone tank, or a softie tank..


New member
Well I used to do water changes every 2 weeks and now I'm down to once a month. I still don't see any real benefit to it. My tank looks no different after a water change. I'm sure it's doing some necessary things I can't see like bringing ion ratios back where they should be (which is important since I dose two-part). But as for controlling nutrients, that's the filter's job. A water change cleans maybe 10-20% of the water and is probably nullified within a day or two. I see water changes as a means of controlling long-term accumulations and deficiencies. So in that respect, a large water change every month or two is probably just as good as small frequent water changes. I don't know if I'd go so far as quarterly water changes, though it may work just fine for the right tank (if they are large %'s). And of course this is all just IMO.