POLL - Big Water Changes - Good or Bad?

[that Fish Guy]

I have heard that Giant Water Changes are great from some people while other people tell me it is a terrible idea.

I always thought that they were a good thing.

The way I see it is you add a ton of Calcium, Magnesium, and Trace Elements.

And also take out a ton of the waste keeping your Nitrates at O which is great for Coral Growth and keeps Algae Down.

What do you guys think?

Please Vote in the Poll too and comment on why you said Good Idea or Bad Idea.

 

[Reefer54]

What does GIANT mean...20%, 50%....20% is the upper threshold in my opinion, and 50 should not be executed unless emergency conditions present themselves. Large water changes shock the tank....there are all kinds of threads here that explore many aspects of this.

adding cal, mag should be done to keep STABILITY, not just to add them or replenish after letting them be stripped of the water..


nitrates should not be 0.....it is not great for coral growth. algae control, yes, but phosphate is going to be the bigger culprit for algae anyway, which you will not be able to keep up with in large water changes if you are not addressing the problem of what is introducing large quantities of P to begin with anyway....again, many threads here discussing this too.

so i vote bad idea, considering 20% not Giant

 

[SS_Sean]

Depends.....:fun4:

 

[ReeferKimberly]

Smaller is better for stability. And like said, corals need some nitrates.

In an emergency, well obviously that is another story.

Stick to 15% changes, imo.

 

[Aran]

I change out 60gallons weekly
--> I have a 120 with a 40gal sump.
->so 150-160 total volume ( sump not filled to top)
so 60/150
-->40%

I do this just because it happens to be the size of my mixing barrel and so I just change one full barrel each week.

 

[KCombs]

I've found that anything under 50% is OK so long as the temp & salinity matches...well I've never lost anything anyway ..For freshwater I don't bother de-chloring....
and BTW NEVER use hot water in your mix, no matter even if the final temp is the same (its nitrogen depleted and it actually matters!)

 

[igot2gats]

Smaller is better for stability.

This.

I assume you mean 30%+ is a big water change. And for the reason above, that is why I voted it to be a bad idea.

Your water params have a greater chance of being a roller coaster with larger water changes.

 

[PL-Reef]

I've always done large WCs. 40% to 60%. Never had an issue.

 

[michaellee64]

20 gallons a week on a approx. 400 gallon system. About every 3 months, 40 gallons a week. No issues with any of my SPS.

 

[joshky]

I do a 25% WC on my 20g tall weekly (I'm only considering a 5g water displacement in my math, it could be closer to a 30% WC.), maybe a bit larger than most do on their tanks; however I run this tank very low maintenance, no dosing, no reactors, no GFO, nothing really. I run a hob filter, which I could probably do without if and when I upgrade my powerheads to wp10's.

When I do my WC, I match salinity / ph / temp perfectly due to it being a nano and the size of the water volume I'm changing. This tank has been going for a year and a half and it's pretty jammed full of corals, it could definitely use an upgrade. But it's a reef I did for my dad and younger brother to enjoy so I don't spend a lot of money on it and an upgrade would be $$$$. xD

Oh and I don't put SPS in this tank, just LPS and Softies. Hence the low maintenance route. I use reef crystals on this tank and all of my parameters remain rather stable with my current WC routine.

 

[ca1ore]

Personally, I would only do a 'large' water change, one exceeding 30% of total volume, in the service of some kind of urgent situation. As a regular part of tank husbandry, I typically do 10% changes every two weeks.

I find that water stability is just as important as absolute values, perhaps more so. No matter how carefully one mixes and measures, new water will always be different than old water (and in many case it is important that it is; nitrate levels, for example) so I avoid large swings by eschewing large water changes.

 

[Sinekal]

In my experience large water changes can be shocking to the stability of the system. I prefer more frequent small changes.

I also only look at changes as a method of maintaining trace elements and keeping ions balanced, core variables like calc and alkalinity need more stability than can be provided in a water change unless you have a low demand system and a frequent/consistent method of doing changes.

 

[that Fish Guy]

What does GIANT mean...20%, 50%....20% is the upper threshold in my opinion, and 50 should not be executed unless emergency conditions present themselves. Large water changes shock the tank....there are all kinds of threads here that explore many aspects of this.

adding cal, mag should be done to keep STABILITY, not just to add them or replenish after letting them be stripped of the water..


nitrates should not be 0.....it is not great for coral growth. algae control, yes, but phosphate is going to be the bigger culprit for algae anyway, which you will not be able to keep up with in large water changes if you are not addressing the problem of what is introducing large quantities of P to begin with anyway....again, many threads here discussing this too.

so i vote bad idea, considering 20% not Giant

55 Gallon - I change 20 Gallons every week but the it seems more like 60 to 70 Percent is changed over 36% because Aquariums are always less Gallons that they claim and the Rock and Sand Displace Water too.
29 Gallon - 12 Gallons changed every week
10 Gallon - 4 Gallons every week
20 Frag - 8 Gallons every week

But all these Tanks seem to go down 60-70 Percent based on what I said above.

I Heat the Water Before I put it in and make sure that the Salinity is the Same too.

 

[ahmed_iAM]

Really depends on the system. I have a high nutrient tank and a low nutrient system. For the low nutrient I do a 15% change weekly while 5% for high nutrient systen

 

[swclown]

20-25 gallons per week on 155 gallon with 30 gallon sump. the only time i've done large ones is during a crisis or a move to a larger tank. too much swing and instability for my taste.

 

[snorvich]

I do 20% twice monthly.

 

[ReeferBill]

I am with snorvich on 20% two times per month!

 

[tonymission]

I do 10% weekly. Tank seems to be doing better than when I did 30% monthly but I really didn't know what I was doing then either so the difference is way more than just my WC.