Poll: 100% water change - Successful?

[cthoughts1]

Hey guys, recently I engaged in a discussion about performing a 100% water change on your existing reef tank. It appears that theoretically such a water change can be done, but I would like to know if practically it has ever been done, and done successfully, by an average reefer.

I will not inject my opinion at this point so as to not influence the results, but I am very curious to hear about your experiences.

Please ONLY vote for the first two options based on your actual experience and not theoretical belief. The last two options are there for you to vote based on your beliefs.

Thanks!

 

[Lenny718]

I once transferred from a 90 gallon to a 150 gallon with a 100% new water and had no spike or "mini cycle" whats so ever. Your beneficial bacteria is on the rock and in the sand not in the water column.

 

[cthoughts1]

Lenny, you placed everything from your 90g into your 150g and put 100% new water in your 150g, discarding all the water from your 90g?

Were able to match all the water perameters so as not to lose any fish or any coral? What water perameters did you check for in doing so? Thanks.

Also, I know you are a bit more experienced in this hobby, is this something you would recommend doing to an average reefer?

 

[Lenny718]

Lenny, you placed everything from your 90g into your 150g and put 100% new water in your 150g, discarding all the water from your 90g?

Were able to match all the water perameters so as not to lose any fish or any coral? What water perameters did you check for in doing so? Thanks.

Yes. The parameters I checked where salinity, temp and PH. I lost no livestock in the process. I recently did it again on a smaller scale, I went from a 24g nano cube to a 45g cube tank with 20g sump. Again replacing all the water with new water and again no loss in livestock and not a trace of ammonia or nitrite.

 

[cthoughts1]

So you never checked for calcium, alk, mag, po4, etc? Just asking because I hear that a drastic change in any of these could shock the system and with all new water I'm certain that these were different. Anyhow what was your livestock in the small tank? Any corals?

 

[TRIGGERMAN]

I agree your bacteria is mostly in your rock/substrate I have done 100% changes as well.

 

[masterswimmer]

I've done 100% WC's when treating for red planaria. My skills in doing fast water changes are masterful. I have the all new replacement water on standby, with a strong Euro Utility Pump 5500 to get the new seawater back into the system as quickly as possible.

Like Lenny, I only test the water's parameters for pH (most critical IMO), temp and salinity.
No losses, nothing so much as looking stressed. On the contrary, everything looked amazingly healthy after a 100% wc.

Russ

 

[TRIGGERMAN]

yea clean water is good water I notice my cichlids always color up like crazy after a full change

 

[richardhmc]

I have done 100% water changes twice! I had to empty my tank down to the sand bed to rearrange the rockwork, and once to clean off the hair algae. I lost no coral or fish. Everything was in great shape the next day

 

[JARRETT SHARK]

I went from a 75gal to 220gal with all new water and no problems
you will be suprised how Live rock does for you

 

[Chris Jury]

I've done very large (90%+) water changes many times for various reasons. If the water is well mixed and aerated, the proper temp and salinity, and the water change is done at a reasonable pace (i.e., not leaving critters out of water for too very long) it shouldn't be problematic, and it never has been for me. It's preferable to do several smaller changes under ordinary circumstances, I think, but if the situation calls for it, a big water change can be a very good thing. I've never had any problems result from a very large water change (if done properly, of course), and I don't see any good reason to expect there would be problems. I mean, why would there be?

cj

 

[straightjiggy10]

I did a switched all the rock and sand from a 120 to a 220 with new water and no cycle, i also added 100lbs of cured live rock

 

[TripleT]

The risk outweighs the advantage.

People new to the hobby should not attempt this.

With adequate filtration and skimming, what would be the advantage of doing a 100% water change?

How would you minimize stress to your livestock during this?

100% isn't possible with sand in the tank. And trying to drain your sand would be a bad idea... so nobody try that.

In an emergency (toxin introduced) I might empty most of the water in the tank. Then perform a couple of partial water changes on what's left. Then refill the tank. However, if my fish weren't showing signs of stress, I'd just do a large water change, and put a PolyFilter pad in my sump.

 

[Dre]

It can be done but i wouldn't do it with my stock unless it's an emergency.The best people to ask about this is the Venders at the Swap, i'm sure they have done it on occasion but not me i always use some of the old tank water.:biggrin:

 

[cthoughts1]

I've read the warning labels on many products that are dosed in fish tanks such as phosphate removers, nitrate removers, calcium and alk. suppliments etc, and they all warn not to over dose so as to not change the perameters of your tank too quickly, because it may shock the systm. In my opinion changing the water on such a large scale would ultimately change many of these perameters immediately and even if you match the salinity, the ph and the temperature, in my opinion this would likely cause harm to the system. This would be especially so if such a water change were done by a novice to average reefer who wouldn't realize that they would have to reacclimate their fish and would likely be unable to properly match the ph and salinity. I would not advocate using this meathod to a novice or even a reefer of average experience.

 

[ming]

I have done a 100% water change on both times I've done a tank move/upgrade with no issues. Although if you move, and have algae on the walls of the tank, especially nuisance algae, that algae will become dry/die from being exposed to air too long and WILL cause an ammonia spike which I have also experienced killing anything alive in the tank. (This happened because of lack of sleep for 36 hours straight and I was too tired from a move) If you're able to to pump new water in at the same time pumping water out, then I certainly see absolutely no issues. (You might be pumping some of the new water out due to circulation, but that's fine. The only time I would recommend a 100% water change though, is in an extreme emergency and NOT part a routine maintenance.
I do it in a tank upgrade as well simply because I just think I'll be starting fresh with all parameters pretty much reset in case there are any contaminants over the years.
When upgrading to a brand new tank/equipment, I never had an issue.
I will be doing my 100% water change again in the coming weeks when I do my final last upgrade to my new tank!

 

[KathyC]

I also have done this during an upgrade with no issues with the tank, nor did I lose any fish or corals due to the change.

This should only be done when there is an emergency within the tank or during an upgrade (why would you add old water to a new tank?).
In a properly maintained reef tank, this should not be a necessity, nor should it be routinely used during water changes.

Obviously, all corals and fish & critters should be acclimated over to the new water when a 100% change is necessary.

 

[jaa1456]

I have done this many times over the years do to upgrades or total rip downs of tanks. Just acclimate everythiing before you put it back in except the live rock. although you should rotate your live rock when adding it into the tank to allow air bubbles to escape which would cause die off on the rock where the air is trapped. And whats the difference from moving fish or corals from your old tank to a tank with new water? It's the same exact thing you do when you buy the fish and corals and bring them home.

 

[AlohaTropics]

It can be done as long as pH remains the same with the 2 waters, dkh, pretty much all parameters must remain constant so as not to hurt anything. There is an ionic balance in the water. There is also a ORP reading, and the redfield ratio. The issue is this, when you do small water changes, you are shifting all of these ratios subtly. A 100% water change, though can be perfectly safe, may have a drastic effect in some systems to these balances. All of the standard measured parameters may be the same but again, ionic balance, ORP, redfield, are just a few ratios that we hobbyists normally dont measure or even can if we wanted to. Potentially, this shift may not harm corals directly, but another thing to consider is if the large shift kills off beneficial bacteria which causes a recycle of the tank.

The problem is, 100% or near 100% water change brings too many radicals into the equation. It could do no harm, or it could kill everything. Why run the risk? Also, its a tremendous waste of money.