Montipora losing colour and spotty bleaching

[Fishjayfonz]

Hello all,

Dealing with some odd bleaching which has continued to escalate over the past 2 months or so. Monti's are very pale in the centers but some edges show new growth and great color. Usually bleached spot will appear in the middle and grow outward. Any thoughts? Picture shows the start of all these headaches around 2 months ago.

Tank parameters:

Temp: 76.8-77.4
Salinity: 35ppt-35.9ppt
Alk: 165-175ppm
Ca: 400-440
Mag: 1350-1450
PO4: 0.02-0.15
NO3- : 4-5
NH4: 0.01-0.02
NO2- : 0.001-0.005
K:400-440

Largest swings would be Alk drops ~10ppm (0.5dkh) over 2/3 days as I am manually dosing it. PO4 is controlled using LaCL3 and experiences major swings post dose or once dose has lost its efficacy, swings about 0.1ppm during that time. As for other parameters, I'd say flow is pretty poor (5x tank volume) and indirect and the colonies are getting PAR between 40-110.
Had an ICP test done recently which showed nothing alarming but a high Lanthanum concentration at 0.012ppm but I'm dosing for it so that makes sense.

My guesses so far as to what's causing this are:
1. Too little light
2. Dirty RODI ~20TDS
3. LaCL3 precipitation issues (dripped through 100micron sock)
4. Too large of PO4 swings/ lack of nutrients

Would appreciate any advice or discussion

Happy Reefing,

J

 

[vetteguy53081]

Mag a little high and insufficient lighting
Moderate light and good water flow
Phosphate <.04
Check also for pests with flashlight
Temp 76-79
Ph 8.1-8.3

 

[Rmckoy]

Are the huge range in values accurate ?

alk 10ppm is huge . Especially for sps
As well as mag . Seams unlikely to have 100ppm mag swing
What kit are you testing with ?
Try to focus more on stability and dose accordingly frequently .
smaller doses throughout the day are always better than less frequent larger doses

 

[Fishjayfonz]

Are the huge range in values accurate ?

alk 10ppm is huge . Especially for sps
As well as mag . Seams unlikely to have 100ppm mag swing
What kit are you testing with ?
Try to focus more on stability and dose accordingly frequently .
smaller doses throughout the day are always better than less frequent larger doses

I'm using multiple kits for each parameter and test daily so I'm somewhat confident in the accuracy using hanna checker and acid titration for Alk, Salifert + aquaforest for Ca and Mag, Hanna ULR phosphorous and a Hach machine for PO4. The ranges I've given have been the parameters for the past two months, but daily swings are much less, ~5ppm alk, Ca stays very stable as does Mag. Trying to split up Alk dosing and PO4 dosing more as those are the major swings I'm noticing in the system.