Do bare bottom reef tanks need water changes?

gbpackers

New member
Hi, I am just wondering if bare bottom tanks need water changes or if it is enough to siphon detritus from the tank routinely and call it good after blowing off the rocks.

The reason I ask is because I have a bare bottom 40 breeder with 0 total dissolved solid water and nitrates at 0. I am having algae problems with a new LED light I just got. My tank is 5 years old and I am getting more algae on the rocks and glass that I'm used to with increased photo period Which is about 8 to 10 hours. I'm wondering if I need to do regular water changes or what I have been doing is just siphoning detritus out of the tank every 2 days. I know the standard is if you have algae keep your nutrients low but mine already are.

I have a hang on back skimmer and only two clownfish and one six line wrasse so I am not overstocked.
I have also been considering adding a sump and in sump skimmer but I don't know if that would really make a difference or not. I don't want to do a sump and buy a skimmer and build a new tank if all I need to do is change more water or do something else different.
I just have soft corals and I do have a Ducan and one brain coral.
Thanks
 
Water changes are used for mutliple reasons, 1 of which would be replacing minerals. You can do no water changes but you should dose

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Do you have a result for a phosphate test? Even with Nitrates and Phosphates showing very low test numbers they are being consumed quickly by the algae. A large WC will greatly reduce those nuisance nutrient levels. You have to complement that with constant manual removal.

Also check the white channel intensity on your new lights. That greatly contributes to algae growth in my experience.
 
Do you have a result for a phosphate test? Even with Nitrates and Phosphates showing very low test numbers they are being consumed quickly by the algae. A large WC will greatly reduce those nuisance nutrient levels. You have to complement that with constant manual removal.

Also check the white channel intensity on your new lights.That greatly contributes to algae growth in my experience.
I don't have a phosphate test. I thought there was some issue about certain types of phosphates not showing up on tests regardless of if they were present.
I will start doing water changes in addition to siphoning.
What channel intensity an I shooting for? Do you just mean the brightness, or is channel intensity something different? I can manually program the light.
Thanks
 
Hi, I am just wondering if bare bottom tanks need water changes

They need more. "Generally speaking".

A DSB works as a buffer for a while, without that buffer they ae easy to get away from you with water quality.

Different methods are used to keep water cleaner and which method you choose determines water quality and how often a change is required.
 
This. Much more important reason for WC's than nutrient export, if you are using other means like skimmer, refugium, etc.

Yeah, this is what I was wondering. I do have an aquamaxx HOB skimmer which works ok, but mainly I siphon detritus out every 2-3 days and blow the rocks off and don't do water changes. I was kind of trying to figure out if it's worth adding a sump and in sump skimmer, but it almost sounds like just doing water changes would be more effective??
 
How does one siphon detritus out without needing to replace water after?

Gavel vac into a high micron filter sock into the sump. That's how I have been doing my system works great. If you mean the detritus that accumulates in the sump I use a shop vac with a 1/2" PVC pipe to suck out the very bottom and replace the 1 gal or so every month.
 
How does one siphon detritus out without needing to replace water after?

I just siphon it out with a turkey baster in the few piles that accumulates in. It amounts to about 16 to 24 oz of water that I take out every time I do that. That doesn't alter anything much and I have an automatic top off.
 
I just siphon it out with a turkey baster in the few piles that accumulates in. It amounts to about 16 to 24 oz of water that I take out every time I do that. That doesn't alter anything much and I have an automatic top off.

You are going to see some decent salinity drift over time if you don't account for that. Pulling that saltwater out and replacing it with freshwater via ATO will do that. I hope you are adjusting for that.
 
You are going to see some decent salinity drift over time if you don't account for that. Pulling that saltwater out and replacing it with freshwater via ATO will do that. I hope you are adjusting for that.

Yep, I am. I watch it and add salt water occasionally, but based on what everyone is advising I'm going to just do more standard water changes too.
Do you think a sump and in sump skimmer would help, or are the larger water changes the most important thing?
Thanks
 
Unless you have other means of nutrient export(fuge, nitrate reactor, carbon dosing, gfo, etc.) then water changes are the only way to maintain your nutrients at a reasonable level. Detritus will get stuck in your rocks and you will never get it out in time for it to not be an issue.

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Also, fish pee. That is an ammonia supply that will be turned into nitrates through your tanks biological process. There's no way to siphon that out with a turkey baster.

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Water changes are necessary for all the reasons others have said.
LED lights are quite intense, I turned mine down to 40 blue and 20 white and lowered the
Photoperiod to 8 hours only. Once all the algae was gone...through carbon dose and agent green, about 6 weeks, I turned them up to 60 blue and 40 white.
In my case, the carbon dose energized the biological filter and the agent green zeroed out the phosphate....now more light is possible because the algae has no phosphate to grow.
 
Unless you have other means of nutrient export(fuge, nitrate reactor, carbon dosing, gfo, etc.) then water changes are the only way to maintain your nutrients at a reasonable level. Detritus will get stuck in your rocks and you will never get it out in time for it to not be an issue.

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Ok, I guess I need to step up my water changes. I don't run GFO.
Thanks
 
Water changes are necessary for all the reasons others have said.
LED lights are quite intense, I turned mine down to 40 blue and 20 .
I think I may need to turn my brightness down some more. The LED's are much more intense than what my corals are used to.
Thanks
 
I have never used a sump. Your tank is 5 years old...that's certainly mature.
But you did change your light.....so good idea to turn down.
You mention higher than corals are used too.....as along as you bring the intensity up slowly over time, you can achieve great coral growth without bleaching them. Like anything in our hobby....consistency is everything and change is OK when it is done slowly.
 
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