I am going to set up a refugium with chaeto and put in on a reverse lighting schedule to help keep my PH up at night. How much chaeto will I need to stabilize a 130 gallon reef? Will a basketball sized clump be enough? Once I find out how much I will need, I can decide on the size of the fuge.
How much macro?
- Thread starter tooshay
- Start date
kmk2307
Active member
Hey tooshay,
I think that would be a great size to start out with. It really depends on the amount of nutrients in the system rather than the size of the system. Try to find the clump's maximum growing size and keep it pruned back to that size. If you prune it to be too small it will take a while to get back to exponental growth and your system my suffer. If you let it get too big it could use all the nutrients up and slow down in growth or could even die out. I would think at bare minimum you should be looking at a 30 or 45 gallon refugium for that size reef, again depending on what kind of load you have. On a side note is there any reason you want to do a reverse night cycle instead of 24/7? It seems chaetomorpha can grow just fine under these conditions and it saves you from buying a timer and you end up with more nutrients being taken out of the system faster.
Just my $.02,
Kevin
I think that would be a great size to start out with. It really depends on the amount of nutrients in the system rather than the size of the system. Try to find the clump's maximum growing size and keep it pruned back to that size. If you prune it to be too small it will take a while to get back to exponental growth and your system my suffer. If you let it get too big it could use all the nutrients up and slow down in growth or could even die out. I would think at bare minimum you should be looking at a 30 or 45 gallon refugium for that size reef, again depending on what kind of load you have. On a side note is there any reason you want to do a reverse night cycle instead of 24/7? It seems chaetomorpha can grow just fine under these conditions and it saves you from buying a timer and you end up with more nutrients being taken out of the system faster.
Just my $.02,
Kevin
Kevin, thanks for the advice. I am having a problem with my PH dropping at night. I had to put a fan over my sump to speed evaporation so I can top off with 2 gallond of kalk daily. The PH goes from 8.2 in the evening to 7.6 in the morning before the light come on. I don't need the macro for nutrient export, but to try to get my PH to stay up at night. Would I still need such a big fuge for this purpose?
I have a goofy sump that takes up half the space, but I could take it out and make a new sump/fuge combo. I have a 16"X53" space under the stand without the current sump. I would need to cut the front brace (While supporting it with a 2X4) and re-attach it after the sump is in place. Hmmm, I will be moving within a year and plan to upgrade to a 150. Maybe I should find another solution to my PH swings until the move? Unless I could fit enough chaeto in a 10 gallon to do me any good.
piercho
New member
Ouch. Don't you, in a way, "go with it?"
Well, it sounds like you understand that addition of the limewater will pull the pH up by taking up CO2 from the solution, and it should be added at night when pH is low. Dropping to 7.6 from 8.2 is a pretty big deviation. Most people keeping reef tanks that use limewater have the opposite problem, that pH tends to run too high. Do you recon your kit (or pH monitor) could be way off?
Could you add 2-part buffer in addition to limewater? With your pH running so low, you could push the TA (total alkalinity) up to 4 meq/L, or even higher, with additions of ESV B-ionic (or a similar 2-part) without getting too much calcium carbonate precipitating out . Like limewater, 2-part buffers push up pH. This is the easiest way to increase the pH (and keep TA and Ca++ balanced) that I can think of.
More direct gas exchange at the air/water interface should also help by allowing the tank to gas off CO2 faster. Moving air through the stand and hood should lower the ambient CO2 in the area where it is exchanging with your tank water. Directing more air and water flow at the water surface should also encourage gas exchange. Some new houses are sealed so tightly that they have problems with chronic high CO2, and in that case you'd have to solve that problem for increased agitation to improve CO2 release from the tank water.
So there are three easy answers:
1. pH isn't getting measured correctly to start with.
2. Add 2-part buffer to "consume" more CO2 in the solution if your TA isn't already high.
3. Allow the tank to gas off more CO2 by increasing air and water agitation at the surface, and venting more air through the tank and hood.
Consumption of CO2 by plants is, IMO, mostly a function of light intensity, available nutrients, and water flow by the plants. What plants you introduce to your tank and the volume of water where the plant production is occuring is secondary. I introduce desirable plants to my system because I'd rather grow them than have uncontrolled production of undesireable plants in my system. Chaeto is desirable but does not always grow well for everybody.
I guess what I'm saying is that I'm guessing that a 10G refugia could consume enough CO2 to bump up your pH, if the water flow through the refugia is enough and the light is bright enough. I'd also hedge my bets with a variety of algaes instead of just chaeto.
"Dyanamic Aquaria", Adey and Loveland, is one of the few books that discusses primary production and it's interelationship with water chemistry. It's too academic for most reefers but should be well within a RN's understanding. Some saltwater books by Steven Spotte have very good discussions of the mechanics of gas exchange, and these are often available through the library system. I have a xeroxed Spotte reference I could send as a .pdf next week that covers gas exchange, but not how photosynthesis effects tank pH.
piercho, thanks so much for the detailed response. I have used a Salifert and Seachem test kit, and not believing the low readings, I bought a Pinpoint PH monitor. All have read basically the same. I use "Reef Buffer" by Seachem to keep my alkalinity between 4-5meq/l, and "Reef Complete" for my calcium suppliment. I have 2 Maxi-jet 900's and 3 maxi-jet 1200's all pointed at the surface for incredible agitation. I have a fan over the sump to allow me to top-off 2 gallons of limewater. I usually add 1 gallon in the am, and 1 gallon before I go to bed. Any more info that you have would be welcome. Thanks again for the great response
Bill, I mix up the kalk and let it sit for several hours or overnight and only add the clear liquid on top. Is that the right thing to do? I usually add the gallon over a period of an hour, but I picked up some IV tubing last night at work and I am going to rig up a drip system that will drip throughout the night. Hopefully this will keep the PH more stable and prevent the drop in the am.
piercho
New member
This is the best way, IMO. A milky solution would raise your pH and lower your need to add alk and Ca with other buffers. Adding milky limewater also adds those things that would have precipitated out and not got added if you only added the clear solution. The limewater should be stored in a container where it doesn't get much exposure to air. Once it's mixed, you should avoid additional agitation. Assuming that you are adding a slight excess of lime, not leaving it in an open container, and not agitating it, it will remain at full potency for a fairly long time.
What I would do is see what the equilibrium pH of the tank water is. Take out 2 gallons of water from your system into a 5G bucket. Aerate it vigourously for 6 hours or so with the air pump located inside the stand. Check the pH. Is it around 8.1, or lower? Now do the same thing with the bucket and air pump located outside. Now what is your pH?
If, in both cases, the pH comes out to something close to 8.1, you know that your problem is inadequit gas exchange to keep up with the tank load. Increasing plant production can help with this. Improved aeration would also help. You are already running your TA pretty high, so you don't have much room to consume CO2 by buffering unless you choose to add milky limewater and reduce/cease the other buffer additions.
What if the equilibrium pH when you took air from the stand is low? To me, that would indicate that the air local to the stand, or inside the house, is CO2-rich. What if the equilibrium pH when you took air from outside is low? Now you are dealing with a water chemistry issue that would best be discussed on the Chemistry forum.
Your doing all the right things, it sounds like. I fought a high pH problem for 1.5 years before getting the daily variance down to + 0.3. It took a plumbing modifiation that increased the systems gas exchange.
That is about all I have to offer. Good luck.
I like to add fresh mixed milky kalk. I mix just enough to use at one time to replace any H2O from evaperation. The milky stuff is a little stronger and will do better at raising your alk and thereby giving you a more stable pH.
Kevin,
I couldn't resist resist busting your chops for having such a clean refugium I'll be waiting for a pic of the wierd algae
Kevin,
I couldn't resist resist busting your chops for having such a clean refugium
I'll be waiting for a pic of the wierd algae 
