# why is algae bad?



## Aquarius Keeper (Sep 22, 2008)

I've heard a couple times now that one reason a lot of current is required is to prevent algae from taking hold. I personally don't mind the look of algae and would even guess that, as in fresh water setups, it actually improves water quality via added biological filtration and oxygenation (my turtle tank has become much healthier since I let algae take hold, and now even support healthy fish).

Other than aesthetic preference, are there any other reasons/consequences to consider in trying o inhibit or promote algae growth in saltwater setups?

Thanks,

Jonathan


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## conger (Feb 2, 2008)

what follows is only one man's opinion...

the first two things that come to mind, depend on (1) what kind of saltwater tank you are keeping, either reef or fish-only, and (2) what kind of algae you are talking about.

If you are keeping a reef tank, the water quality needs to remain pristine, meaning 0 nitrates... algae other than coralline cropping up is a sign that the water quality is suffering, which might mean your very expensive corals are at risk. For a fish-only tank, I don't think this would really be a problem as you can let nitrates creep up as high as 10-20 ppm for most SW fish, so if you don't mind hairy rocks/substrate and keep an eye on the nitrate level, you might be alright ;-). Either way, a SW tank probably shouldn't rely on algae growth to provide biological filtration... hopefully you'll have enough live rock and sand in the tank to provide all the bio filtration you need.

And as far as what kind of algae you are talking about, any type of algae other than coralline would be competing with coralline algae (which most people really like) and possibly hindering its growth. I can't imagine anyone prefering green/brown hair algae over red, purple, and pink coralline algae. Of course if you are talking about coralline algae to begin with, then I would say it IS desirable, as healthy coralline growth indicates proper calcium levels and generally good water quality. And if you see cyano growing ("red slime algae", even though its not REALLY algae, but a bacteria colony), it will spread rapidly, is extremely tough to get rid of, and is a dead indicator of poor water quality (or at least an excess of something that shouldn't be present in ideal water).


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## Aquarius Keeper (Sep 22, 2008)

Thanks for the detailed response!

I am setting up a small FOLR tank - I'm asking mainly because I've read a couple times that without proper current algae will develop, and I was just curious why that was considered a bad thing. 

On an aesthetic level, I actually like the way green algae looks. I mean, obviously with some trimming/cleaning so it doesn't obscure the main view into the tank. I love it in my turtle tank, and it definitely makes a positive difference for the fish I keep with my turtle - (keeping a turtle tank cycled is hard!)

BTW is there anything to do to encourage the coralline?


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## conger (Feb 2, 2008)

well hopefully someone else will chime in as well, and fill in my gaps or correct me where I might be wrong :lol:

I'm no expert on this subject, but coralline algae definitely needs sufficient calcium levels, which will likely need to be supplemented as I don't think any salt mix contains sufficient calcium by itself (could DEFINITELY be wrong there). But also to keep calcium levels at a stable, high level, you also have to be sure to keep your alkalinity and magnesium levels stable and within "safe" ranges as well, each of which could also require supplementation. Of course it needs sufficient light as well, I *think* more than the green and brown types that most people consider nuisance algaes. In short, coralline requires very intentional effort to get it to grow.

Also, keep in mind that coralline algae is just that, algae: it will compete with other types of algae for nutrients, so its probably unlikely that you will have heavy green/brown algae growth as well as a pretty explosion of coralline. Hopefully my explanation gives you some good basic info, but again I'm hoping that someone else with more knowledge and experience than me chimes in and either confirms, supplements, or denies what I've stated here 8).

One other point, is that having good water flow/turnover rate in your tank is important for more than just keeping algae down... since your live rock will be the main source of biological filtration and will play and important role in the health of your tank, you want to be sure that you have a good flow of water over and through the rocks! And lastly, the ocean is a very dynamic environment, with constant flows and gusts of current... thus the fish you keep in your tank will feel more at home in a tank with water flowing about , as opposed to the more stagnant/slow flow of many freshwater tanks.


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## onefish2fish (Jul 22, 2008)

conger said:


> One other point, is that having good water flow/turnover rate in your tank is important for more than just keeping algae down... since your live rock will be the main source of biological filtration and will play and important role in the health of your tank...


good water flow also aids in good oxygen levels. oxygen isnt the same as it is in freshwater.

also, have you ever seen a green hair algae infested tank?


its not pretty.


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## Aquarius Keeper (Sep 22, 2008)

Believe me I get it about the importance of circulation and oxygenation in general!

But I know this old fish keeper who runs a shop downtown - he's been doing it for over 30 years - and in many of his tanks he sort of cultivates algae as part of the aquarium system - I think it's quite beatiful actually.

Of course, all things in moderation - I'm not talking about a habitat being overrun with algae - but it's like all gardening - a little ivy is quite nice, but if you're not tending to it, it will choke out everything else...


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## onefish2fish (Jul 22, 2008)

i think you may be confusing cheato algae with green hair algae.

chaeto algae is GREAT for a sump or soap dish in the display,
hair algae is ugly and nasty for... anywhere IMO


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## onefish2fish (Jul 22, 2008)

put i do see what you are saying, my freshwater tank's backwall is completely covered with reg. old green algae.. you can still see through it so i still have a background but i never scrape it off, i only scrape the sides and front glass.
it gives a constant food source for my guppies to nibble at.


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## Kellsindell (Sep 15, 2008)

onefish2fish said:


> i think you may be confusing cheato algae with green hair algae.
> 
> chaeto algae is GREAT for a sump or soap dish in the display,
> hair algae is ugly and nasty for... anywhere IMO


I have heard a lot of people enjoying the way gha looks, and i myself hase been one of them, but after i realized why it was there in the first place, i made plans on riding myself of it.


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