Do these Zoas look happy?

[paul.o]

Had these in the tank about a couple of months always in the same location, they have always been open but I'm not sure they are as open as they should be, plus they don't seem to be growing much, if at all. Tank is relatively new about 3 months old started with dead rock. Zoa's are on the sand in the bottom left of the tank, Tank is red sea nano max using just the return pump for water movement with no powerhead.
Latest tests were-
alk 10.9
calcium 420
phos 0.12
nitrates 25

Alk is high as the salt has high levels (instant ocean). I am dosing all4reef.

 

[reeftivo]

look fine to me

 

[Reefer911]

Not your question but I’d add a power head to get more flow, and those brown spots on the sand might clear up

 

[shakacuz]

they seem pale, but very likely due to the white lighting. otherwise i don't see an issue.

 

[jkcoral]

They look pretty good. Sometimes zoanthids just take a little while to get established before they pick up the pace on growth.

Just make sure you are feeding them once a week to help them out. And I agree with the other comment, a powerhead would be good. Zoas benefit from a little bit of flow, it helps them clean out gunk that is in their connective mat and helps them stay healthy.

 

[Narideth]

Also good to note - some zoanthids just don't grow as fast as others. My bambams practically push out a new head every week but I have a group of utter chaos that has kept the same 4 heads for 6 months and only now is starting to push out a new one.

Also different strains of the same grow at different paces - a second utter chaos mini colony has been in my tank for two months and I see new heads developing. Big shrug, but yours look healthy to me.

 

[paul.o]

Thanks for the replies, I guess I'll just leave them to it.
I did have a jebao sw4 in the tank but it was too strong even on minimum, there is a gentle flow from the return so I was hoping to do without an internal powerhead, I'll see how bad the sand gets.

 

[littlebigreef]

They appear to be healthy white walkers, good coloration and over all appearance.

Generally, the observation that zoas grow at different rates is correct. However, some zoas can (and do) go into stalls- usually after fragging/shipping/moving. Doesn’t mean they’re unhealthy, they’re just not growing.

Bear in mind water parameters (nutrients) are an indirect measurement of actual nutritional input. Whether aminos, phyto, roids, frozen food slurry or fish poop zoas love to eat. Depending on the polyp they like eating different sized stuff as well. If nutrient input/export is low that’s a good place to start. Given your tank is cycled but still maturing I think you’re in a good spot.

As for alk it’s been my experience that zoas don’t mind if it’s high or low so long as it’s stable.