Anoxic layer disturbance

[Sirhcpordlaw]

Good morning fellow reefers! I'm new to this forum so I would like to introduce myself. My name is chris and I live in memphis, tn. I've been doing some research (about a year) into the hobby prior to setting up my 90g. I decided to incorporate a DSB into my reef. I had an incident last week that claimed my watchman goby, both peppermint shrimp, skunk cleaner, and a dozen narcissius snails, and a half dozen Astrea snails. My hello tang is okay. Pistol shrimp is good, Sally lightfoot is good and my emerald is fine as well. All of my corals looked a little sick for a few days and finally are fit. Pulsing Xenia was never phased. I'm afraid that I may have disturbed the DSB and wiped out half the tankmates. Is this likely? Water parameters are: nitrate 0, nitrite 0, ammonia 0 , ph 8.4, kh 100 - 200, phosphates 0, salinity 1.025, copper is undetectable. I waited for two days and introduced 4 more narcissius and thy died within minutes. Anyone have any advice? Currently been doing weekly 11% water changes with salt water purchased from my lfs.

[SPasse]

Sirhcpordlaw,

If the coral is looking better, you are probably over the worst part. The couple of times that my DSB got disturbed & caused an issue, I just waited it out, with more water changes than normal in the interim.

Talk to me about the worms etc. that you used to establish your DSB.

Regards,

Scott

[Ninong]

Hi Chris,

I decided to incorporate a DSB into my reef. I had an incident last week that claimed my watchman goby, both peppermint shrimp, skunk cleaner, and a dozen narcissius snails, and a half dozen Astrea snails. My hello tang is okay. Pistol shrimp is good, Sally lightfoot is good and my emerald is fine as well. All of my corals looked a little sick for a few days and finally are fit. Pulsing Xenia was never phased. I'm afraid that I may have disturbed the DSB and wiped out half the tankmates.

Is this likely?

No, I don't think it's likely, especially in a tank that has only been set up for about six months.

Water parameters are: nitrate 0, nitrite 0, ammonia 0 , ph 8.4, kh 100 - 200, phosphates 0, salinity 1.025, copper is undetectable.

What brand of test kit are you using for your alkalinity measurements? It's unusual to have your alkalinity range that much -- 100-200 ppm CaCO3 equivalents (2-4 meq/L, 5.6-11 dKH).

Are you testing for calcium and magnesium?

I waited for two days and introduced 4 more narcissius and thy died within minutes. Anyone have any advice? Currently been doing weekly 11% water changes with salt water purchased from my lfs.

What brand of salt?

What you are describing is very unusual. Last week you lost your watchman goby, three Lysmata spp. shrimp, a dozen Nassarius and half a dozen Astraea, plus an additional four Nassarius that died within minutes after you added them.

Here's one more question, what brand of copper test kit did you use? And does it have an expiration date on it?

Check all of your equipment to make sure everything is fine and nothing is messed up, especially anything electrical like pumps that come into contact with the tank water.

Good luck!

[Sirhcpordlaw]

Copper test is API and is not expired. Magnesium is tested 360. Calcium is 500. All other parameters are the same. Started doseing magnesium to raise but still do not feel warm and fuzzy yet. Not comfortable not knowing for sure what happened. Noticed that skimmer hasn't been skimming since this happened. Alklinity test is also API and salt is instant ocean.

[Ninong]

I'm going to forget about trying to figure out why some of your tank's inhabitants are doing fine and others are dropping like flies as soon as they are added to the water and instead concentrate on trying to figure out what's going on with your water chemistry.

You previously said that you are purchasing your saltwater from your LFS. Is that correct? And they're using Instant Ocean, right?

What you have to do next is you have to test a batch of this saltwater before using it for your next water change. First thing you need to do is measure the salinity. Full strength seawater is S=35 (35ppt or 1.0264 SG). You previously stated that your specific gravity is 1.025. That's acceptable but a little on the low side and it will result in your other measurements being slightly lower than normal seawater. I wouldn't let it go any lower than 1.025 SG for a reef aquarium. Some people like to use lowered salinity for fish-only tanks but I don't think it's a good idea to go lower than 1.025 SG in a reef tank.

After you test the salinity of the saltwater you are using, you will need to test the pH, calcium, alkalinity and magnesium. The reason I am saying that this is necessary (very necessary) is that you previously stated that you are doing weekly 11% water changes and yet you are reporting a magnesium measurement of 360 ppm. Something is WRONG with this picture. VERY wrong!

That's assuming your magnesium measurement is correct.

However, I'm having a hard time trying to reconcile a magnesium measurement of 360 ppm with normal pH (you reported 8.4). You reported 500 ppm Ca, which is certainly acceptable, although slightly higher than normal. Normal calcium is ~420 ppm and anything between 400-500 ppm is acceptable, although the target most people shoot for is 425-475 ppm.

I'm a little confused by your alkalinity measurement and wonder why you reported it as 100-200? I'm assuming you mean 100-200 ppm CaCO3 equivalents, which would be 2-4 meq/L or 5.6-11 dKH, but that's a very unusual way of stating alkalinity and an extremely wide range. What test kit are you using for alkalinity?

Have you noticed any calcium carbonate precipitation in your tank? For example, on the equipment?

Ignoring the fact that some of your animals are doing fine and others are dying on impact, I have to say that I have never really considered what the toxicity effects of depleted magnesium might be on marine life. Obviously if your magnesium is really only 360 ppm, then the effects should be very obvious.

The seawater concentration of magnesium is 53 mM compared to 10 mM calcium. In other words, there are 53 ions of magnesium for every 10 ions of calcium. Only sodium and chloride are present in higher concentration. Magnesium is lighter than calcium, so on a weight basis, there is approximately three times as much magnesium as calcium, ~1285 ppm Mg and ~420 ppm Ca.

Magnesium is so important to the chemistry of the other ions in the water that I'm not sure how you could have 8.4 pH, 500 ppm Ca and, I assume, somewhere between 5.6-11 dKH alk. However, if I accept that you have 360 ppm Mg, then I can see why you would have problems keeping some animals alive. I think the lowest I ever got was around 1050 ppm Mg and that was because I wasn't paying attention and wasn't doing water changes frequently enough and didn't realize that dripping limewater didn't do anything for magnesium. That was during my first few months in the hobby. After that I started using ESV's magnesium chloride additive to keep magnesium in balance.

I guess the bottom line is that I'm at a loss to explain why you are losing snails instantly and yet your xenia is plusing away and your "hello" tang is fine. Is that supposed to be "yellow" tang?

Usually the first thing you look for when snails die suddenly is copper poisoning. Copper will kill snails at concentrations much lower than those required to harm fish. Then if you raise the concentration a little more, polychaete worms will start crawling out of the sand bed and the live rock and dying. So snails die off first, then worms, then fish if the concentration gets much higher. We have had reports of hobbyists who killed off snails, worms AND fish by unknowingly using brass fittings in their tank's plumbing. And other hobbyists who killed off just the snails and worms by using a glass tank that had previously been dosed with copper medication and not thoroughly decontaminated before being used as a reef tank.

Anyway, start out by testing the saltwater before adding it to your tank to make sure there is nothing wrong with the saltwater. And, yes, we have in the past had reports of EXTREMELY bad Instant Ocean salt. So bad that the alkalinity measured an incredible 95 dKH. That's not a typo. It was so high it couldn't be tested with hobby test kits and had to be tested in professional laboratory. That was several years ago and it was caused by an undetected bad batch that was shipped. However, it did cause several hobbyists to lose everything in their tanks.

Good luck!

[Sirhcpordlaw]

Please excuse the hello tang. I'm posting from my iPhone and sometimes it has a habit of sneaking one in on me. Yes that would be a yellow tang. Yes the Lfs I get my water from uses instant ocean. I measured tank parameters today and Mg 1260 ppm, Ca 400ppm, KH 196.9 ppm, ph 8.4, salinity 34, nitrate 20 ppm, nitrite 0, ammonia 0, phosphate .5 ppm.
Rookie mistake on the Mg test. I read the scale backwards. Still a tad low but nowhere as low as I thought.

Not sure where I got mixed up the last time postin KH. It was at 196.9 then as well. Nitrate is elevated because I skipped my last water change because I panicked thinking that my lfs nuked my tank with off water. I will get back on the wagon on my next day
off. Going to kill some aphasia during the next water change. I'm claiming that I do 11% water change since I'm using 5gal buckets with a 90g tank. Skimmer is working again. Check valve was plugged. Starting to feel relief. Also happy that ammonia hasn't spiked due to the dead things that are still M.I.A. My hermits are enjoying their new shells though.

[Ninong]

Okay, at least that mystery is resolved. I suspected that your reported Mg reading had to be in error.

Your 20 ppm Nitrate is certainly acceptable at this stage of the game. You should want that to fall below 10 ppm and you should want your phosphate to drop from the 0.5 ppm down to under 0.03 ppm.

One other point, alkalinity is almost never reported as ppm CaCO3 equivalents. Your reading of 196.9 (which is unusually refined) should be reported as either 3.9 meq/l or 11 dKH. Just divide the ppm CaCO3 equivalents by 50 to get milliequivalents per liter and then multiply that by 2.8 to get degrees Karbonate hardness, which is the traditional German unit of measurement. Milliequivalents per liter would be the metric units of measurement. Milligrams per liter (mg/l) is often used in place of ppm (parts per million) and there is only an extremely tiny difference between them.

[Sirhcpordlaw]

Talk to me about the worms etc. that you used to establish your DSB.



I added red spaghetti worms, bristle worms, sand sifting clams, and Nassarius Snails. I have a 90gal with about 5" sand bed that is half sand and half crushed coral. I don't see much of the bristle worms or the clams but the spaghetti worms can always be seen around an uneaten food pellet or some detritus. i only added a dozen and now they can be seen al over the tank. I didn't have to add pods. i just let them hitch hike off the live rock. My pistol shrimp and zebra hermits do a good job of stirring up the top layer as well. I ordered the worms, clams, and hermits from IPSF since none of the LFS sell anything like that around here. You pretty much have to hope for it to come in on LR.

[reeferbill]

Talk to me about the worms etc. that you used to establish your DSB.



I added red spaghetti worms, bristle worms, sand sifting clams, and Nassarius Snails. I have a 90gal with about 5" sand bed that is half sand and half crushed coral. I don't see much of the bristle worms or the clams but the spaghetti worms can always be seen around an uneaten food pellet or some detritus. i only added a dozen and now they can be seen al over the tank. I didn't have to add pods. i just let them hitch hike off the live rock. My pistol shrimp and zebra hermits do a good job of stirring up the top layer as well. I ordered the worms, clams, and hermits from IPSF since none of the LFS sell anything like that around here. You pretty much have to hope for it to come in on LR.

I think you had an ammonia spike when you lost a fish and it snowblled from that. I would do 20 percent water changes until the nitrates and phosphates are at zero.

[reeferbill]

Talk to me about the worms etc. that you used to establish your DSB.



I added red spaghetti worms, bristle worms, sand sifting clams, and Nassarius Snails. I have a 90gal with about 5" sand bed that is half sand and half crushed coral. I don't see much of the bristle worms or the clams but the spaghetti worms can always be seen around an uneaten food pellet or some detritus. i only added a dozen and now they can be seen al over the tank. I didn't have to add pods. i just let them hitch hike off the live rock. My pistol shrimp and zebra hermits do a good job of stirring up the top layer as well. I ordered the worms, clams, and hermits from IPSF since none of the LFS sell anything like that around here. You pretty much have to hope for it to come in on LR.

I forgot to mention about doing 20 percent water changes every week and then test. test. test. when you go back to your regular skedule. Happy Reefing!!!!!!!

[Ninong]

The clams bury under the sand bed and if you look very, very hard, you might see their siphon. The next time you see a clam on top of the sand bed, it will be dead. How long have you had them? These clams (Tapes philippinarum) usually do not survive more than 9-12 months in a typical reef aquarium.

The bristle worms can be seen if you look for them after all lights in the room have been off for a least an hour. Use a red flashlight or a regular white flashlight with red cellophane covering (or a screw-on red plastic lens cover). Any astronomy supply store will sell red flashlights. They're used by amateur astronomers to read their charts and instruments without messing up their night vision. If you use a regular white flashlight without a red covering, you will have to look very fast because the bristle worms (Eurythoe complanata is what IPSF sells) will retreat instantly when hit by regular white light. They can't see red light.

How long has it been since you added the dozen spaghetti worms that you now see all over the tank? I assume that it must be at least 9 or 10 months or more, right? These guys bury in the top layer of the sand bed with just their buccal tentacles showing above the sand. They aren't really all that mobile. It takes them quite a while to move from one spot to another. They just wait for food particles to drift over above their tentacles so that their tentacles can reach it.



P.S. -- If you mix crushed coral with sand, the sand will eventually move to the bottom and the crushed coral will rise to the top.

[Sirhcpordlaw]

I'm not detecting amonia in my weekly tests however I've been expecting it. I've seen hermits wearing some of the shells of the snails I lost and was not able to find so i know that their rotting little carcases are somewhere in my tank

I've had the clams and worms for about 6 months (I guess I should have said that in the first post.) I was replying to Spasse who had asked in an earlier thread what I had in my DSB

I've also seen the crushed coral seeping up as the sand bed got stirred but it doesn't seem to be causing any trouble.

I've been doing weekly 15gal water changes since my snails and shrinp died. I've since added another batch of snails and they are doing just fine. Hopefully I'm back on track.

[Ninong]

I've also seen the crushed coral seeping up as the sand bed got stirred but it doesn't seem to be causing any trouble.

The infauna that inhabit a true sand bed, one composed of sand, are not the same as those that inhabit a bed of crushed coral. The size of the particles is very important to the infaunal critters. Those that live in fine-particle sediments (sand) cannot live in crushed coral -- two entirely different environments.

A sand bed does not need to be stirred and should not be stirred. That defeats the purpose of having a sand bed in the first place. By stirring it you disrupt the infaunal balance and diminish its capacity for beneficial biological filtration.

Over time, your sand will settle to the bottom and your crushed coral will rise to the top. Large particles like crushed coral cannot support the same microcrustaceans and tiny polychaetes that inhabit fine particle sand -- two different environments entirely. Crushed coral should not be mixed with sand.

You might want to read this article by Dr. Ron Shimek on sand beds.



P.S. -- Another, more detailed, article on the functioning of a sand bed: Part 1 and Part 2, by Dr. Rob Toonen.