Exposure during a water change

[Long Time Beginner]

When I do a water change, the water level drops and the top several inches of my live rock are exposed to the air. I try to move fast to limit the exposure time, but it still happens for at least 5-10 minutes with each water change. It's not a huge deal right now but I'm worried about what happens when I start adding coral. Fish can swim to the bottom but coral can't!

What do other people do about this? Do you just let stuff be exposed to air for a few minutes? Keep live rock only in the bottom half of the tank? Add your new water in gradually while you're still taking the old water out so the level doesn't drop much?

[kenman345]

How much % change you doing how often? whats the size of the tank? Maybe you might want to do smaller changes, or do the change, by doing just enough before it gets exposed, then adding in water, then a few minutes later just for peace of mind that its evenly mixed in) you do the same thing until your water change is complete. Overall, you would still be getting much of the benefits of the water change, but in the instance that you are removing some of the new water as well as the old, you should probably add more % water change to help counteract the inherent loss you have by doing it in stages.

[Long Time Beginner]

Originally Posted by kenman345

How much % change you doing how often? whats the size of the tank? Maybe you might want to do smaller changes, or do the change, by doing just enough before it gets exposed, then adding in water, then a few minutes later just for peace of mind that its evenly mixed in) you do the same thing until your water change is complete. Overall, you would still be getting much of the benefits of the water change, but in the instance that you are removing some of the new water as well as the old, you should probably add more % water change to help counteract the inherent loss you have by doing it in stages.

It's a 54 gallon corner tank, with a 15 gallon sump. I change 16 gallons per water change. It's still a fairly new tank (~ 2 months) so I'm changing every 2 weeks, but would eventually like to get that to once per month after the tank is a little more stable.

[kenman345]

Hmmm.....You may do better with doing the water change from the sump instead of the display.

[Reef Frog]

I wondered about this too when I started out. But no need to worry. Every coral I've seen closes up and the slime coat can keep it hydrated for quite some time. 10-15 minutes is no problem. In the wild, many corals are exposed to the air & sun on a regular basis during tidal movements. Natural selection has provided the solution. But on the other hand, don't go outside and paint the house in the middle of a water change.

Just to be safe, I'll squirt exposed coral with a turkey baster in the rare event they need to be exposed for longer periods even though they'd be fine without doing this.

My observations here might not apply to diseased, stressed or delicate corals that have not yet acclimated. And it's a no-no for sponges.

[skippy2]

A lot of my corals and rock is exposed to air for sometimes up to a 1/2 hr. Hasn't hurt anything in the 12 yrs. I've been doing water changes.

[Long Time Beginner]

Originally Posted by kenman345

Hmmm.....You may do better with doing the water change from the sump instead of the display.

I've thought about this, but I like to do my water changes by vacuuming the junk off the tank floor. Hard to do that from the sump

[Long Time Beginner]

Originally Posted by Reef Frog

Every coral I've seen closes up and the slime coat can keep it hydrated for quite some time. 10-15 minutes is no problem. In the wild, many corals are exposed to the air & sun on a regular basis during tidal movements.

Originally Posted by skippy2

A lot of my corals and rock is exposed to air for sometimes up to a 1/2 hr. Hasn't hurt anything in the 12 yrs. I've been doing water changes.

Thanks, these statements help put my mind at ease!

[m0nkie]

I'm more concerned about the water being pumped back into the DT...

the DT gets drained, the sump gets filled.. when water returns to DT, the pressure from nozzle is huge. I'm more scared of that stirring up everything.. I try to keep it under the water surface, but that's not always possible.

[Long Time Beginner]

Originally Posted by m0nkie

I'm more concerned about the water being pumped back into the DT...

the DT gets drained, the sump gets filled.. when water returns to DT, the pressure from nozzle is huge. I'm more scared of that stirring up everything.. I try to keep it under the water surface, but that's not always possible.

My tank is barebottom, so there's not as much to stir up. Just a problem if any coral decide to grow under the nozzles (my sump return is forked).

[tkeracer619]

Depends on the coral but it happens all the time in nature for stuff that lives at the surface.

[Mcgeezer]

Your changing 16 gallons on a 54 gallon tank every two weeks? That's way too much turn over on your water column. Try doing about 30-35% water change monthly. You want to maintain your established bacteria,especially in a new tank.

You can alleviate this by doing smaller weekly changes. I have a 70 gallon with 20 gallon sump and I change 5 gallons weekly. Keeps it simple and also replenishes trace elements for my reef while also removing any additional dissolved organics that my skimmer misses.

[CuzzA]

Originally Posted by Mcgeezer

Your changing 16 gallons on a 54 gallon tank every two weeks? That's way too much turn over on your water column. Try doing about 30-35% water change monthly. You want to maintain your established bacteria,especially in a new tank.

You can alleviate this by doing smaller weekly changes. I have a 70 gallon with 20 gallon sump and I change 5 gallons weekly. Keeps it simple and also replenishes trace elements for my reef while also removing any additional dissolved organics that my skimmer misses.

The bacteria is not in the water column. Water changes never hurt. If we could change all the water in our tanks everyday all of the inhabitants would greatly appreciate it, but obviously that's not practical and cost prohibitive. Remember we strive to mimic the ocean and natural reefs are constantly supplied with new water moving in and out.

[m0nkie]

Originally Posted by CuzzA

The bacteria is not in the water column. Water changes never hurt. If we could change all the water in our tanks everyday all of the inhabitants would greatly appreciate it, but obviously that's not practical and cost prohibitive. Remember we strive to mimic the ocean and natural reefs are constantly supplied with new water moving in and out.

I think I remember 1 member here that does 100% water change.. crazy..

[Roger30]

I had this question on sponges! I know sponges can not be exposed to air. Do you just place them at the bottom of the tank?

[m0nkie]

Originally Posted by Roger30

I had this question on sponges! I know sponges can not be exposed to air. Do you just place them at the bottom of the tank?

haven't had a sponge yet, but I read that they require medium flow and medium light. There are some that prefers light, but most prefer shades. So I assume somewhere low and under rock shade would be ideal..

[CuzzA]

Originally Posted by Roger30

I had this question on sponges! I know sponges can not be exposed to air. Do you just place them at the bottom of the tank?

Unfortunately, there isn't a lot of information on sponges. The consensus from most hobbyists is sponges are difficult to keep alive. Some can be exposed to air, but the vast majority cannot. Some are toxic to a tank when they die. The greatest problems with keeping sponges is feeding them without compromising your water quality and suffocating them from algae growth. They require a ton of flow with very little light. Which is hard to achieve as most tanks have the majority of flow near the surface where there is a lot of light.

I think where they were collected and mimicking the exact environment makes a difference as to their survival in captivity.

I have one sponge in my tank. An orange tree sponge. It's been rather difficult to keep happy for the six months that it's been in there. But I've learned what it likes and it seems to be doing well now. Very minimal light. I have it under a ledge. Any part that is exposed to light immediately grows algae and must be cleaned off. I also target feed it every other day with phytoplankton which for me isn't necessarily a bad thing as I have other filter feeders such as clams and feather dusters. Plus I do 15% weekly water changes and keep up on my GAC and GFO.

Here's an interesting video on sponges. You can see why they need a ton of flow.

http://youtu.be/m8a0oNsDEx8

I'll add that if you're going to try and add a sponge to your system, buy the smallest one you can... Easier to find the right spot in your tank and easier to feed.

[mypepper]

For myself, I have a 90 gallon reef, which I only exchange 6 gallons of salt water every week during my routine tank cleaning.

Just remember, nothing happens fast in this amazing hobby of reef keeping and take your time and don't rush mother nature or it will take a toll on your tank, fish and corals. Both my tangs are now reaching the 20 year mark with me and that only due to my dedication of routine water changes and keeping things simple.

For the past 45 years, I've employed the KISS theory when maintaining my tanks and it's worked for me.

Good luck with your new tank and keep reading this forum for all the information you will need as you learn this incredible hobby, which I got hooked early in my life.

Randy