I have been fighting high nitrates for some time now. All other water parameters are fine. Ammonia=0, Nitrites=0, Calcium=400, ph=8.2, Nitrates=12.5 to 25, alk=3.0. I'm running a k2r calcium reactor. Modified berlin skimmer. External filter for carbon. I went to add some live rock to the tank and noticed that the sand bed is hard as a rock. What would cause this?
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Sand Bed setting up like rock.
- Thread starter USMC81
- Start date
If your sandbed is completely rock solid all the way down my guess is that it could be a significant contributor. DSB's primary function are denitrification (along w/ liverock). If your sandbed is rock solid there are two options you have:
1) leave the sandbed in place and just go with it
2) pull the old sandbed out and replace it all with new sand
We'd need all of your system details to help you more (tank size, sand used, lbs rock, filtration, feeding, etc)
Shane
1) leave the sandbed in place and just go with it
2) pull the old sandbed out and replace it all with new sand
We'd need all of your system details to help you more (tank size, sand used, lbs rock, filtration, feeding, etc)
Shane
Tank, Equipment, Live Rock & Sand
Tank size is 38 gal. 36" x 12" x 20.5"
Lighting - (2) 55 watt Power Compacts
60lbs. Live Rock (Tonga & Figi Mix)
3.5 to 4" Sand Bed (started with Caribsea live sand bags then added live sand purchased from LFS).
10 gal. sump w/ modified Berlin Classic Skimmer
K2R Calcium Reactor
External filter (hang-on type) for carbon
Livestock
(4) Chromis Damsels
(1) Rainford Gobie
(1) Small Scopus Tang
(2) Peppermint Shrimp
Corals
Large Galexia
Lettuce Leather
Toadstool Leather
Multitudes of various mushrooms
Xenia
Pagoda Cup Coral
Feeding
Seaweed/Algae sheets daily
Frozen brine shrimp every 2 to 3 days
Water Parameters
Calcium-400
Ammonia-0
Nitrite-0
Ph-8.18 @ day 8.00 @ night
Alk-3.0
Nitrate-15 to 25
Tank size is 38 gal. 36" x 12" x 20.5"
Lighting - (2) 55 watt Power Compacts
60lbs. Live Rock (Tonga & Figi Mix)
3.5 to 4" Sand Bed (started with Caribsea live sand bags then added live sand purchased from LFS).
10 gal. sump w/ modified Berlin Classic Skimmer
K2R Calcium Reactor
External filter (hang-on type) for carbon
Livestock
(4) Chromis Damsels
(1) Rainford Gobie
(1) Small Scopus Tang
(2) Peppermint Shrimp
Corals
Large Galexia
Lettuce Leather
Toadstool Leather
Multitudes of various mushrooms
Xenia
Pagoda Cup Coral
Feeding
Seaweed/Algae sheets daily
Frozen brine shrimp every 2 to 3 days
Water Parameters
Calcium-400
Ammonia-0
Nitrite-0
Ph-8.18 @ day 8.00 @ night
Alk-3.0
Nitrate-15 to 25
If you where dosing kalkwasser like there was no tomorrow then that might lead to your sand bed cementing. Generally, it means the alk/ca system is out of whack.
BTW why do you think you need a k2r calcium reactor on a 38 gallon tank with few stony corals? Sounds like an overkill.
You could easily get by with a simple two part every once and awhile.
10-25 ppm nitrate is not unreasonable.
Yup, second the idea of testing your source water. In general use the purest water you can find (ro/di, distilled water, etc).
Good luck.
Scott
BTW why do you think you need a k2r calcium reactor on a 38 gallon tank with few stony corals? Sounds like an overkill.
You could easily get by with a simple two part every once and awhile.
10-25 ppm nitrate is not unreasonable.
Yup, second the idea of testing your source water. In general use the purest water you can find (ro/di, distilled water, etc).
Good luck.
Scott
First off how old is your tank? How do you make your water? Is there any sponge material in your hang on filter? How old is the sand bed? Be carefull not to feed too much with frozen shrimp, I found this to be a food source that can pollute the water easily.
I personally don't think sand bed is that benefical, I know this will offend some people but there is very little denitrification going on in most tank sand beds. I run my alkanity higher than you and when I added my cal reactor 6 years ago my sand bed started to harden. Its pretty dam hard now and I have no issue's. Your ph is off in my opinion, this may be due to your cal reactor. Try to find ways to increase the gas exchange with your set-up. For instance in my case My ph was doing the same thing as yours except my alk was higher(12dkh). I had a big skimmer but my sump(75gal) had a glass cover on it. I removed the cover on my ph rose .2 degree's. Are you using too much Co2 for your flow rate? I hope you get the picture. Also it took me about a year to get my nitrates below 5ppm. I stopped checking them about 5 years ago at that time I couldn't read any. Remember coral uses nitrate's as food source.
I presently measure ph, alk, salinity, and temp. But most importantly I just look at everything and you can tell when things are off.
Bill
I personally don't think sand bed is that benefical, I know this will offend some people but there is very little denitrification going on in most tank sand beds. I run my alkanity higher than you and when I added my cal reactor 6 years ago my sand bed started to harden. Its pretty dam hard now and I have no issue's. Your ph is off in my opinion, this may be due to your cal reactor. Try to find ways to increase the gas exchange with your set-up. For instance in my case My ph was doing the same thing as yours except my alk was higher(12dkh). I had a big skimmer but my sump(75gal) had a glass cover on it. I removed the cover on my ph rose .2 degree's. Are you using too much Co2 for your flow rate? I hope you get the picture. Also it took me about a year to get my nitrates below 5ppm. I stopped checking them about 5 years ago at that time I couldn't read any. Remember coral uses nitrate's as food source.
I presently measure ph, alk, salinity, and temp. But most importantly I just look at everything and you can tell when things are off.
Bill
I've got a few ideas but not the expertise to give you a good answer. Maybe point you in the right direction though...
*A sandbed infauna population is supposed to keep the sand from lumping with all their movement.
*When the Nitro-type bacteria first goes through their cycling bloom, then they give off a mucous-type-something that will harden.
*There's a way to tell if calcium is the culprit by either soaking a lump of hardened sandbed in (ok, here's where my memory fails me)... vinegar or bleach. (I think that it's bleach)
*A sandbed infauna population is supposed to keep the sand from lumping with all their movement.
*When the Nitro-type bacteria first goes through their cycling bloom, then they give off a mucous-type-something that will harden.
*There's a way to tell if calcium is the culprit by either soaking a lump of hardened sandbed in (ok, here's where my memory fails me)... vinegar or bleach. (I think that it's bleach)
FWIW, low pH won't cause your sandbed to cement contrary to what was said above. Low pH actually should *dissolve* your sandbed. Remember, aragonite is calcium carbonate and reacting calcium carbonate with an acid will bring calcium into solution and evolve carbon dioxide. A *high* tank pH, however, can and will cause this. When I say high pH, I mean that the tank has to experience pH's above 8.4 for extended periods of time, such as when you are dripping kalkwasser.
Also, if you are overdoing it on calcium/alkalinity additions, this can also contribute. Your tank water can only hold so much calcium and alkalinity before it starts to come out of solution. You may want to recheck how quickly your tank uses calcium and alkalinity and readjust your calcium reactor accordingly.
Here's how to test if it's a bacterial biofilm or if it is calcite precipitation:
* Take a chunk of your sandbed and place it in bleach. If the sandbed particles fall apart, it's a bacterial biofilm that is cementing the sandbed together.
* Sometimes, tho, bleach isn't enough and if it doesn't fall apart in bleach, take a new chunk of the cemented sandbed and boil it on the stove in tap water. If the sandbed chunk falls apart, it's a bacterial biofilm.
If the sandbed stays rock hard after these two tests then your sandbed cementing is not being caused by bacteria and is being caused by calcite precipitation onto the sandbed grains.
You did not mention if you were using RO/DI water for all of your makeup water. If you are not, then this could be a possible nitrate source. Test your water that you are using to topoff your tank for nitrate.
Personally, a nighttime pH of 7.99 and daytime pH of 8.12 is pretty darned close to what you want to be running. Ideally you'd like to shoot for 8.2 but you're very close to that even during the night. Heh, I've seen tanks run at 7.7 night / 8.2 day and the stony corals were jamming.
fwiw
Shane
Also, if you are overdoing it on calcium/alkalinity additions, this can also contribute. Your tank water can only hold so much calcium and alkalinity before it starts to come out of solution. You may want to recheck how quickly your tank uses calcium and alkalinity and readjust your calcium reactor accordingly.
Here's how to test if it's a bacterial biofilm or if it is calcite precipitation:
* Take a chunk of your sandbed and place it in bleach. If the sandbed particles fall apart, it's a bacterial biofilm that is cementing the sandbed together.
* Sometimes, tho, bleach isn't enough and if it doesn't fall apart in bleach, take a new chunk of the cemented sandbed and boil it on the stove in tap water. If the sandbed chunk falls apart, it's a bacterial biofilm.
If the sandbed stays rock hard after these two tests then your sandbed cementing is not being caused by bacteria and is being caused by calcite precipitation onto the sandbed grains.
You did not mention if you were using RO/DI water for all of your makeup water. If you are not, then this could be a possible nitrate source. Test your water that you are using to topoff your tank for nitrate.
Personally, a nighttime pH of 7.99 and daytime pH of 8.12 is pretty darned close to what you want to be running. Ideally you'd like to shoot for 8.2 but you're very close to that even during the night. Heh, I've seen tanks run at 7.7 night / 8.2 day and the stony corals were jamming.
fwiw
Shane
Here's how to test if it's a bacterial biofilm or if it is calcite precipitation:
* Take a chunk of your sandbed and place it in bleach. If the sandbed particles fall apart, it's a bacterial biofilm that is cementing the sandbed together.
* Sometimes, tho, bleach isn't enough and if it doesn't fall apart in bleach, take a new chunk of the cemented sandbed and boil it on the stove in tap water. If the sandbed chunk falls apart, it's a bacterial biofilm.
If the sandbed stays rock hard after these two tests then your sandbed cementing is not being caused by bacteria and is being caused by calcite precipitation onto the sandbed grains.
Your the man Shane.
Liquid,
Thanks for all of the info. I took a chunk out and put it into some bleach and it did not fall apart. Then boiled it on the stove. It started to fall apart after a few minutes. As far as make up water is concerned. I get that out of my tap run through a tap water purifier. I tested it and it has 0 nitrates.
Plankton,
Thanks for your info. I had the K2R calcium reactor on a previous larger tsystem. I had to shut that system down and replace it with a smaller system during a move to a new house. I hate to not use it. easier than having to remember dosing with a two part additive.
WildBill,
Thanks for your info as well. The tank and it's inhabitants are around 1.5 years old. Water is through a tap water purifier. No sponge material. Sand bed is same age as tank. The Co2 rate is adjusted for the flow rate. Effluent ph is 6.7, as the manual said it should be. I tested the calcium in the effluent and it is 650. The tank calcium is 400.
Thanks for all of the info. I took a chunk out and put it into some bleach and it did not fall apart. Then boiled it on the stove. It started to fall apart after a few minutes. As far as make up water is concerned. I get that out of my tap run through a tap water purifier. I tested it and it has 0 nitrates.
Plankton,
Thanks for your info. I had the K2R calcium reactor on a previous larger tsystem. I had to shut that system down and replace it with a smaller system during a move to a new house. I hate to not use it. easier than having to remember dosing with a two part additive.
WildBill,
Thanks for your info as well. The tank and it's inhabitants are around 1.5 years old. Water is through a tap water purifier. No sponge material. Sand bed is same age as tank. The Co2 rate is adjusted for the flow rate. Effluent ph is 6.7, as the manual said it should be. I tested the calcium in the effluent and it is 650. The tank calcium is 400.
WildBill,
"there is very little denitrification going on in most tank sand beds."
Why on earth would you say this? 8O 8O 8O Don't get me wrong, I'm not offended - that would be stupid. I'm just curious as to what EMPIRICAL DATA you have that warrants such a statement. There is certainly plenty of empirical data to the contrary, including much which I myself can provide, as can many other members of this board.
Maybe a better statement would be that your tank is doing fine without a sandbed.
Regards
Jim
"there is very little denitrification going on in most tank sand beds."
Why on earth would you say this? 8O 8O 8O Don't get me wrong, I'm not offended - that would be stupid. I'm just curious as to what EMPIRICAL DATA you have that warrants such a statement. There is certainly plenty of empirical data to the contrary, including much which I myself can provide, as can many other members of this board.
Maybe a better statement would be that your tank is doing fine without a sandbed.
Regards
Jim
Column in November FAMA magazine talks about cementing of sandbeds preventing the required diffusion needed to have plenum based denitrification working. Ultimately this resulted in chronic high nitrates (and fish crash) though Amonia and Nitrites remained in check. Could happen in a DSB as well I suppose.
JimM,
I do have a sand bed and yes my tank is very healthy. My present tank was put up in 94. Before that I ran 180 with no sand and had great results. I am aware of alot of the data that is out there, trust me I don't think my way is the only way. I think that most sand beds in mini reefs have alot of dead zone's. I don't think we should assume that all sand beds are playing a active role in the denitrification process. Yes in some tanks this could be the case(healthy) but I'm sure there is an equal amount of sand beds that don't contribute much. What would you say is the greatest factor that play's in the denitrification process in your reef? Either way I thank you in advance for your comment.
USMC81,
I still think you should work on your ph. What kind of test kit are you using to get a measurement of 650cal. I don't use a K2R but instead I use a double chamber MTC. I measure the alk output. Correct me if I'm wrong but I thought it was not possible to have cal level's that high with normal alk readings. Also have you calibrated your probes lately? When my sand bed was soft (pre cal reactor) my ph rarely got up over 8.25. Now it never goes below 8.20.
Bill
I do have a sand bed and yes my tank is very healthy. My present tank was put up in 94. Before that I ran 180 with no sand and had great results. I am aware of alot of the data that is out there, trust me I don't think my way is the only way. I think that most sand beds in mini reefs have alot of dead zone's. I don't think we should assume that all sand beds are playing a active role in the denitrification process. Yes in some tanks this could be the case(healthy) but I'm sure there is an equal amount of sand beds that don't contribute much. What would you say is the greatest factor that play's in the denitrification process in your reef? Either way I thank you in advance for your comment.
USMC81,
I still think you should work on your ph. What kind of test kit are you using to get a measurement of 650cal. I don't use a K2R but instead I use a double chamber MTC. I measure the alk output. Correct me if I'm wrong but I thought it was not possible to have cal level's that high with normal alk readings. Also have you calibrated your probes lately? When my sand bed was soft (pre cal reactor) my ph rarely got up over 8.25. Now it never goes below 8.20.
Bill
I use the Red Sea Pharm Calcium Test Kit. Being color blind, most of the other test kits are hard for me see. But this test kit i really see the change in color.
I monitor the ph of the effluent coming ut of the reactor to assure that it is running properly. I was curious to see what it would read if I tested the calcium levels out of the reactor.
I just recalibrated the probes last Friday. Ph never goes above 8.25
Alk. stays @ 3.0meq/l or 8.4dkh.
I monitor the ph of the effluent coming ut of the reactor to assure that it is running properly. I was curious to see what it would read if I tested the calcium levels out of the reactor.
I just recalibrated the probes last Friday. Ph never goes above 8.25
Alk. stays @ 3.0meq/l or 8.4dkh.
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