How to check on CUC?

[RickvD]

Hello everyone.

I have some questions about my CUC...

I started with 2 nassarius snails,

1 turbo snail,

2 glass snails (not sure what their name was, they were pointy and not too big),

1 small red hermit and 1 big blue hermit.

 

Now I have for some reason lost all snails and maybe a hermit... The big blue hermit is happy as can be and really active so that isn't the problem.

However the 2 nassarius snails come above the sand maybe once a week (that I notice), and often make me think if they are even still alive. The turbo snail died a few days ago (pretty sure he was flipped over and killed if I look at the position of his shell). My 2 other snails where always on the glass, and all of a sudden neither of them were alive. My small hermit is very active at night, I however am not, so for now I think he's fine.

 

I check my parameters regularly and everything is fine. Not even an ammonia spike (that means the last few CUC is doing its job right?).

 

The thing I'd like to know is how I can keep track of my CUC. After my snails died I've noticed algae getting everywhere faster then normal (probably because there are no snails to clean the sand and glass). I'm going to a reef store tomorrow on my day off (The Netherlands is fun, the closest reef store is over an hour away) to pick up 2 more nassarius snails and 3 Nerita SP. Will that be enough to get the upper hand of all the algae on my 15 gal? Or should I buy a few more and let some die off along the way? When everything stabilises, what is the best way to keep track of what is alive and what isn't? Snails etc don't live for that long, and there are so many places to hide...

 

Also, this is my planned CUC for my 15 gal:

4x Nassarius Vibex

3x Nerita SP

3x Clibanarius sp.

3x Paguristes sp. RED

1x Ciliopagurus Strigatus

1x Calcinus Elegans

2x Mithrax sculptus sp.

 

Is this good? I enjoy watching hermits, and I'd love a good mix of colours. Just not sure if those 3 snails can keep the glass clean (I also clean the glass myself at least once a week).

[seabass]

2 hours ago, RickvD said:

Not even an ammonia spike (that means the last few CUC is doing its job right?).

No, that means there is enough nitrifying bacteria (which is never an issue in a mature tank).  Also, if the dead critters were eaten before they were broken down, that helps reduce the ammonia produced.

 

2 hours ago, RickvD said:

I check my parameters regularly and everything is fine.

That's such a general statement (which we often see).  It doesn't really tell us what is being tested, how stable the parameters have been, and the value of each parameter.  For example, some people will say 0.00ppm of phosphate is good (but that low level might be negatively affecting coral health).  Another example might be that you are using tap water with a high copper content (and it's unlikely that you are testing for copper).

 

2 hours ago, RickvD said:

Now I have for some reason lost all snails and maybe a hermit.

There may be an alternate explanation.  Some snails cannot turn themselves upright if they fall on their backs (and eventually die or become prey).  Hermit crabs can sometimes eat snails for their shells, or even for a meal.  Eating too many dinos can be toxic enough to kill animals which eat them.

 

2 hours ago, RickvD said:

After my snails died I've noticed algae getting everywhere faster then normal (probably because there are no snails to clean the sand and glass).xx

Yes, less herbivores will mean more algae.  But also, dying animals release phosphate and ammonia (which eventually becomes nitrate).  We don't know your levels of nutrients to make that call.  Also, is the algae actually dinos?  That might explain the dying cleanup crew.

 

2 hours ago, RickvD said:

I'm going to a reef store tomorrow on my day off (The Netherlands is fun, the closest reef store is over an hour away) to pick up 2 more nassarius snails and 3 Nerita SP. Will that be enough to get the upper hand of all the algae on my 15 gal? Or should I buy a few more and let some die off along the way?

Well nassarius snails are carnivores (they'll eat dead critters and left over food, but not algae).  They also tend to hang out in the sand bed, and only surface when they smell a meal.  If you aren't battling dinos, I'd probably keep a total of about 7 decent herbivores in a 15 gallon tank.  Obviously if your tank is experiencing a dino bloom, the new herbivores will likely die too.

 

2 hours ago, RickvD said:

When everything stabilises, what is the best way to keep track of what is alive and what isn't? Snails etc don't live for that long, and there are so many places to hide...

Observation is the best way to check on the cleanup crew.  Look for snails which are on their backs or not moving.  Dead snails have a bad stench to them, so if you are questioning if they are still alive, take them out of the water and see if they small bad.  There isn't much you can do about those which are hiding; I've never heard of microchipping a snail.

[RickvD]

11 minutes ago, seabass said:

No, that means there is enough nitrifying bacteria (which is never an issue in a mature tank).  Also, if the dead critters were eaten before they were broken down, that helps reduce the ammonia produced.

Alright. The tank is about 3 months old now I think.

 

11 minutes ago, seabass said:

That's such a general statement (which we often see).  It doesn't really tell us what is being tested, how stable the parameters have been, and the value of each parameter.  For example, some people will say 0.00ppm of phosphate is good (but that low level might be negatively affecting coral health).  Another example might be that you are using tap water with a high copper content (and it's unlikely that you are testing for copper).

I use RODI water for waterchanges and ATO. I don't remember my test results from the top of my head, but tomorrow is also water change day which means I'll test everything again. I usually test everything weekly, and specific tests when I feel something is off. I have tests for: NO2, NH4, CA, KH, MG, NO3 and PO4.

 

11 minutes ago, seabass said:

There may be an alternate explanation.  Some snails cannot turn themselves upright if they fall on their backs (and eventually die or become prey).  Hermit crabs can sometimes eat snails for their shells, or even for a meal.  Eating too many dinos can be toxic enough to kill animals which eat them.

This is the reason my Turbo died I think. Just by the way the shell was laying and the fact I needed to turn him over 2 before he died. I don't think I have dino's. Pretty sure it is just basic algae. Doesn't look much different from my freshwater tanks.

 

13 minutes ago, seabass said:

Yes, less herbivores will mean more algae.  But also, dying animals release phosphate and ammonia (which eventually becomes nitrate).  We don't know your levels of nutrients to make that call.  Also, is the algae actually dinos?  That might explain the dying cleanup crew.

After I noticed the snails dieing I tested for ammonia twice a day for about 3-4 days. It never went up.

 

13 minutes ago, seabass said:

Well nassarius snails are carnivores (they'll eat dead critters and left over food, but not algae).  They also tend to hang out in the sand bed, and only surface when they smell a meal.  If you aren't battling dinos, I'd probably keep a total of about 7 decent herbivores in a 15 gallon tank.  Obviously if your tank is experiencing a dino bloom, the new herbivores will likely die too.

Yea the reason I feel like I need 2 more is because the sand is starting to color brown/greenish. So if I'd get 7 serious cleaners like good snails. Could I still add some small hermits just for the fun of it?

 

17 minutes ago, seabass said:

Observation is the best way to check on the cleanup crew.  Look for snails which are on their backs or not moving.  Dead snails have a bad stench to them, so if you are questioning if they are still alive, take them out of the water and see if they small bad.  There isn't much you can do about those which are hiding; I've never heard of microchipping a snail.

I tried the smelling technique on a snail which was definitly dead, didn't smell bad though... I guess I'll just keep watching my tank every day, and when I feel atleast 1/3 of my crew has passed, Ill start adding again.

 

Some pictures of the algae. This is after 6 days with weekly 10% waterchanges and sand/glass cleaning.

 

[seabass]

27 minutes ago, RickvD said:

After I noticed the snails dieing I tested for ammonia twice a day for about 3-4 days. It never went up.

That just means everything is working as expected.  Once the cycle has become established, usually it takes a pretty big ammonia source to noticeably raise levels.

 

27 minutes ago, RickvD said:

I needed to turn him over 2 before he died.

I don't know why, but snails often turn themselves over when they are dying.  Another possible explanation is that the salinity of the water which they were in was notably different than your tank water's salinity (osmotic shock).

 

27 minutes ago, RickvD said:

the sand is starting to color brown/greenish.

Larger grained sand (crushed coral) often takes on color, like your rocks or the tank walls).  Nassarius snails will help disturb the grains, which will only marginally help with the discoloration.  But that's not saying that there isn't enough food for two more nassarius snails (there might be).

 

27 minutes ago, RickvD said:

So if I'd get 7 serious cleaners like good snails. Could I still add some small hermits just for the fun of it?

The pics really don't look too bad, so I probably wouldn't get 7 decent herbivores (may 3 or 4 for now).  And yes, you can get a couple more hermit crabs.  Scarlet Reef Hermits are good, and so are Dwarf Blue Leg Hermits.

 

 

[RickvD]

3 minutes ago, seabass said:

That just means everything is working as expected.  Once the cycle has become established, usually it takes a pretty big ammonia source to noticeably raise levels.

Thats good to know. I've heard somewhere that a bigger snail like a turbo could produce enough ammonia to crash a 15 gal...

 

3 minutes ago, seabass said:

I don't know why, but snails often turn themselves over when they are dying.  Another possible explanation is that the salinity of the water which they were in was notably different than your tank water's salinity (osmotic shock).

I drip acclimate for an hour every time I add something new. Also it's not like they died super fast. They have all been in there for at least 2-3 weeks and the turbo even longer.

 

6 minutes ago, seabass said:

Larger grained sand (crushed coral often takes on color, like your rocks or the tank walls).  Nassarius snails will help disturb the grains, which will only marginally help with the discoloration.  But that's not saying that there isn't enough food for two more nassarius snails (there might be).

Alright. A bit of color doesn't mind, but on a few spots it's clearly algae so that has to go. I also sift my sand before every water change so nothing gets trapped under the grains for to long. I think there will be enough food, at least I hope so.

 

9 minutes ago, seabass said:

The pics really don't look too bad, so I probably wouldn't get 7 decent herbivores (may 3 or 4 for now).  And yes, you can get a couple more hermit crabs.  Scarlet Reef Hermits are good, and so are Dwarf Blue Leg Hermits.

I currently have 1 Scarlet reef (didn't know the name before), wanted to add 2 more of those and 3 dwarf blue so I would have 3/3, and then 2 bigger ones but I might hold off on another bigger hermit. It isn't too bad yet, but I want to get it under control before it gets too bad. What would you recommend? 1/2 more nassarius snails and 3 nerita's? Or is there another snail / combination you would recommend? The fish store I'm going to doesn't have a lot (no hermits etc) but I can order whatever they don't have in stock.

[seabass]

3 minutes ago, RickvD said:

I've heard somewhere that a bigger snail like a turbo could produce enough ammonia to crash a 15 gal...

Nah, but it might cause a spike in a 2 gallon tank.

 

4 minutes ago, RickvD said:

I drip acclimate for an hour every time I add something new.

This is from one of the better snail vendors in the US:  https://www.reefcleaners.org/acclimation

 

6 minutes ago, RickvD said:

I currently have 1 Scarlet reef (didn't know the name before), wanted to add 2 more of those and 3 dwarf blue so I would have 3/3, and then 2 bigger ones but I might hold off on another bigger hermit. It isn't too bad yet, but I want to get it under control before it gets too bad.

The Blue Legs are often considered omnivores, while the Scarlet Reef Hermits are usually considered herbivores (although they are all opportunistic feeders, so they'll usually eat what's available).  When computing cleanup crew numbers, include hermit crabs.  Also keep in mind that you will inevitably lose snails to the crabs (it's a given), and they may fight amongst themselves.

 

12 minutes ago, RickvD said:

What would you recommend? 1/2 more nassarius snails and 3 nerita's? Or is there another snail / combination you would recommend?

There is no perfect combination.  If you are adding a couple of hermit crabs, I might add a couple of nerites too (and maybe one nassarius snail).

[RickvD]

8 minutes ago, seabass said:

This is from one of the better snail vendors in the US:  https://www.reefcleaners.org/acclimation

This is a good read thanks!

 

8 minutes ago, seabass said:

The Blue Legs are often considered omnivores, while the Scarlet Reef Hermits are usually considered herbivores (although they are all opportunistic feeders, so they'll usually eat what's available).  When computing cleanup crew numbers, include hermit crabs.  Also keep in mind that you will inevitably lose snails to the crabs (it's a given), and they may fight amongst themselves.

Yea I have soms shells scattered around the tank to reduce murder, but it is something that I'll keep in mind.

 

9 minutes ago, seabass said:

There is no perfect combination.  If you are adding a couple of hermit crabs, I might add a couple of nerites too (and maybe one nassarius snail).

Alright, I think I'm going to do 2 nassarius snails and 3 nerites. Then wait a week or 2 and order some hermits and some more nerites just to be sure. Thanks for the help!

[Tired]

I would personally avoid the nassarius. They mostly go after uneaten food, so it's better to simply not have much uneaten food and let a hermit or some cerith snails clean up any rare scraps. I'm fond of ceriths to move the sand a little and to serve as general-purpose cleaners, as they mainly eat algae but will also go for scraps, detritus, and dead things.

 

Scarlet reef hermits are fussy about shell shape. Look them up on Google to see the general idea; as babies, they like cerith-style shells, and then they shift into needing heavy, bulky shells as adults. They can be harder to find good shells for, as the shells they like tend to be beat up and not pretty, and are thus sold less. I have a theory that they pick heavy shells due to an instinct to help keep them from getting washed away in waves, not least as I've seen them lift shells as part of the standard hermit new-shell evaluation. I've successfully modified normal hermit shells for scarlet reefs by covering them in a layer of two-part putty to add heft and weight.

 

Algae is inevitable in a reef tank. A healthy reef has its rocks covered in algae. Mainly coraline, but there should generally be some diversity. The goal of a cleanup crew is to keep pest algae from bothering your corals, and a little bit to keep your sandbed and glass slightly cleaner, though those two will require some maintenance on your end as well.