What's the difference?

You often see posts where people are surmising a person has a nitrate or phosphate problem because they are getting algae growth in their DTs. It is usually suggested that the presence of those organic wastes are the root of "insert problem here" and they are cautioned to get rid of them. Typically the OP then states that their test kits read "0" when testing for the nitrate/phosphate which is then met with the assertion that the algae is eating up the nitrate/phosphate as fast as it is being produced, hence the "false" 0 reading. It is then pretty common to suggest using a fuge to eat up all that nasty nitrate and phosphate so you no longer have the water quality related "insert problem here" any longer.

My question is this: Other than aesthetics, what is the difference between chaeto eating up the waste in a fuge vs. other algaes eating it up in the DT? I do realize that excessive waste buildup can reflect poor husbandry practices that need to be changed, however I am primarily talking about the difference in the net effect on water chemistry. I don't see any reason that a clump of chaeto (or an ATS) eating up nitrate/phosphate produces any better water quality than rocks covered in hair algae would if they are both resulting in the 0 reading. Again, aside from the aesthetics, I am having a hard time understanding why the presence of hair or other unsightly algae means poor water quality but a thriving fuge that you pull fist-fulls of chaeto out of does not.

 

I suppose other then looks, some types of algae can be harmful for aquarium inhabitabts

 

Mostly because Chaeto growing in your fuge does not smother our corals and kill them which most nuisance algaes tend to do.There prescence does not mean you have poor water quality necessarily. Don't forget corals use nutrients in order to survive so there total absence is not really something most of us are trying to achieve.The only reason natural reefs aren't covered in algae is not because of water quality. It is because of the prescence of algae eating fish and invertabrates. Take these away and the reefs would be smothered in algae. We are just subsituting one form of nutrient export for another. Having a healthy tank means you achieve a balance between nutrients imported and exported.There are many ways to accomplish this.

 

Although, sadly, this is changing...

 

Agreed- but my main point was regarding the effect on water chemistry.

Understood and I agree 100%. My main point for asking the question was speaking more to assertions I have heard made over and over again for the past few years that the presence of algae in a tank means you have a phosphate/nitrate problem and, more specifically, that a 0 reading test for phosphate really means nothing with regard to the potentially deliterious effects on coral, and that the usage of a refugium will reduce down the levels of nitrate/phosphate to safe levels. I have nothing against the use of refugiums for the export of waste but I do with the logic that a 0 test reading accomplished by a refugium is any different than a 0 test reading by hair algae- on a chemistry basis. The other related issue is the claim that a 0 test reading of phosphate/nitrate does not rule out that phosphate/nitrate can be causing a problem with corals. If that were the case, then ammonia & nitrite should also be considered even though they may also read 0. If testable levels of any of these wastes are 0 then the levels that can potentially interact with cellular tissues of corals and other livetock will also be zero.

 

Think of it more as the algae storing the excess phosphate and nitrate. So, yes, there has been an issue for a long time, it's just not a problem until something goes bad. It's called nuisance algae for a reason. It can kill the corals we are trying to keep.

I agree with Vinny 100% with his answer to your question.

 

Great point. I should have said usually not because of water quality.

 

I'm a little confused by what you are asking I guess if Vinny's answer didn't answer your question. You can still have something causing a phosphate/nitrate problem and various forms of algae consuming it before you can test for it, hence the 0 reading. As far as I know algae doesn't consume ammonia or nitrites, so you wouldn't get a 0 reading because of this issue that you are asking about.

 

All fish tanks have a problem with Nitrates and Phosphates. Its inherent of a closed system. Your right in the fact that regardless of how we export nutrients in our tanks the results will usually be the same.Whether it be algae,macroalgae,GFO,BP's. As long as your keeping the nutrients at levels our fish and corals can tolerate then you have accomplished your goal. With algaes being your form of export,manually removing some from time to time will be necessary.Also most test kits are not very accurate especially when you are testing low levels of these nutrients.A zero reading does not necessarily mean 0. People usually use refugiums to establish Macro algae in hopes it will outcompete other nuisance algaes for food.

 

One must also realize that some nuisance algas release secondary metabolites at certain stages of their life which can be detrimental to other life forms. Surely you've heard of the red tide fish kills in the gulf and along the south atlantic coastline. If cyanobacteria can do all that in the open ocean, just imagine how much worse it would be in the confines of an aquarium if left unchecked. Even some macroalgae species can cause similar problems in confinement. Cheato is one that has been proven to be 100% safe.