Acropora

Many forms of algae growth are caused by excess nitrates in water (typically caused by overfeeding, overstocking, and/or poor maintenance) The reason for this is that these algae consume/tie up nitrates. This is the primary reason for adding macro-algae to sumps or refugiums... so that they can effectively compete with nasty micro-algae (such as hair algae) for resources in the water and starve the micro-algae in the main tank.

 

I've never said I dont have any nitrates...what's the point of DSBs & macros if not to continually lower nitrates? And as a quick heads up - my nitrates were at 40ppm with weekly water changes until a couple months back when i added DSB and macro-algae, and removed bio-balls. Every week nitrates dropped by 10ppm until they were no longer measurable - despite no water changes for that month (mainly because I was curious how low they would go without intervention... i water changed after they stopped registering).... if DSBs and macro-algae aren't converting/consuming nitrates at least at the rate that they are building up in the tank, how were my nitrate levels steadily dropping for a month straight?

 

i didn't believe it would work until i tried it. I was close to giving up on attempting corals because nothing I wanted would tolerate 40+ppm nitrates and I didn't have time to do water changes more then weekly.

one of the kids majoring in marine biology at LFS mentioned he scrapped the sump on the 220gal @ VCU they do studies on once he inherited maintenance and set up a fuge with chaeto and that the levels dropped off within weeks. i figured he was trying to sell me on buying more gear... but i had already just connected the 75 with HOB overflow (with the intentions of setting it up as a dedicated specimen container)... couldn't decide what to put in it so I dumped a ridiculous amount of aragonite & a handful of chaeto, removed the spouts so the 1' PVC just dumped directly in the 75gal (pointed sideways, to minimize current that would introduce O2 into DSB) and it just took off like crazy. One thing to note - I'm having to take handfuls of macro-algae out of the refugium weekly now (which I'm OK with since hair-algae in the main tank has mostly stopped growing and the critters are slowly eating it away)

 

and to make it even harder to believe... it's a 180g with very minimal live rock, and a 75g with modest live rock, and a bare 40g half full... it's alot of water (and thus-alot of nitrates)

The kid also suggested that my nitrate problem could be due to detritus caught in bioballs breaking down and fueling nitrates at the rate i'm removing through water changes... but that doesn't make sense to me since they dropped during a period of no water changes. I'm not going to definitively say the DSB/macro drastically lowered the nitrates (despite that being my reason for adding)... but something had to lower them - my wife's too far along in the pregnancy to be doing water changes behind my back to screw with my head

 

LOL... cold man, cold (Not that I can take too much offense... I had no idea they even had marine biology, I was a computer sciences geek)

That's an excellent question (re what corals)... during one of the long evenings of acropora research, I thought I had pulled information from wetweb regarding pristine water conditions being required, but I cant for the life of me find the information again. Since your obviously not having any problems with your acros... "the proof is in the pudding"... they must tolerate nitrates much more then I understood them to!

 

Hey, I'm always up for advice and new perspectives and I hopefully come across appreciative (which I am!) this thread wouldn't have started otherwise.

I finally was able to dig up the wetweb article regarding water conditions for acroporids: <a class="postlink" href="http://www.wetwebmedia.com/acropt3.htm" onclick="window.open(this.href);return false;">http://www.wetwebmedia.com/acropt3.htm</a>

That article mentions <10ppm... which is what really intimidated me into the mindset that I needed to tinker and try things until I drove mine lower (it's amazing what people do before anyone tells them they cant!)

I do respect Bob's input, but I'm not saying it's 100% right (after all... rarely do our fish and corals read the same books we do regarding their expected behaviors!)

 

I've gotten sign-off from spouse to go kalkwasser... but my anal retentive fears of water shifts (and my strong desire to stop manually topping off daily) has me looking at getting a very large tupperware style trash can or bin, mixing the kalk with RO/DI, and using a float valve and gravity-feeding to sump.

I have 5+ gallons evaporating daily, so I'm seeing the following benefits takign this plunge:

- maintain salinity (although to be honest, the system is so big that salinity doesn't shift in a measurable amount adding 10 gallons of RO DI... more peace of mind)
- maintain calcium (and can adjust how much kalk i mix with each batch to make sure i'm not dosing too much/too little... i'm pretty sure i dont need to add 5 gallons of completely saturated kalk daily...!)
- maintain budget - kalkwasser appears to be a much cheaper alternative to suppliments intended to be dosed. The only cheaper long-term option I see is a calcium reactor, which initial cost makes prohibitive
- maintain laziness. I am SICK of adding 5 gallons daily & dosing daily (and the risk of the pumps burning out if I dont do so).. I'd much rather fill a large container and mix once each weekend.

Any warnings?