Montipora digitata growth issues

[EpicRise]

My Montipora digitata has been stuck at the same size for months. Tank's a 40-gallon breeder, running two AI Primes, params are stable, 8.2 pH, 1.025 salinity, 0 phosphate, 5 nitrate. They're getting spot-fed reef roids twice a week. What's the deal, y'all? Feels like they're just chillin'.

[tidecatcher]

How's your alkalinity? Montis can be picky with alk swings. Mine took off when I locked it at 8.5 dKH. Also, what's your flow like? They dig random, medium flow, not a direct blast. If your pumps are too weak or too predictable, they might not thrive.

[onyxlady]

My Montipora digitata has been stuck at the same size for months. Tank's a 40-gallon breeder, running two AI Primes, params are stable, 8.2 pH, 1.025 salinity, 0 phosphate, 5 nitrate. They're getting spot-fed reef roids twice a week. What's the deal, y'all? Feels like they're just chillin'.

Zero phosphate might be the issue. Corals need some phosphate to grow, even if it's low. Try bumping it to 0.03–0.05 with a tiny bit of fish food or a phosphate supplement. Also, check your magnesium—it should be around 1350 ppm.

[Amigo]

I've had the same problem with my digitata. Turned out my lights were too intense. Dialed back the blues by 10%, and they started encrusting within a week. Maybe try shading them slightly or reducing photoperiod by an hour.

[furry9]

My montis didn't grow until I added more fish. The extra nutrients helped. Maybe your tank's too clean?

[EpicRise]

Appreciate the tips, folks. Gonna test alk and mag tonight, and I'll tweak the flow pumps. Didn't think about the lights being too much—they're at 80% peak, so I'll cut it back a notch.

[tidecatcher]

I've had the same problem with my digitata. Turned out my lights were too intense. Dialed back the blues by 10%, and they started encrusting within a week. Maybe try shading them slightly or reducing photoperiod by an hour.

Yep, light stress can stall growth. If you're running a 12-hour cycle, try 10. Also, what's your calcium at? If it's below 400, they might not have enough to build skeleton.

[onyxlady]

Another thought—how old are your bulbs? If they're past 9 months, the spectrum might be off. Montis can be weird about light quality even if the intensity seems fine.

[Amigo]

Good point on the bulbs. I replaced mine at 8 months last time, and the colors popped way more. Cheap test is to borrow a PAR meter if you can.

[furry9]

Mine grew faster when I moved them higher in the tank. Maybe they need more light, not less?