Grape Caulerpa turn yellow and soften

[BengBear]

Hi,
Bought hand full of 'young and small' Grape Caulerpa and kept them in beta box. They waved gently on 1st day. The next day, realised that half of them turn yellowish from bottom up. Did following:
Kh was somewhere around 5 because of water change. Ramp up to near 7Kh, temperature steady at 29 deg C. Zoa corals were doing well.
Added salifert Iodine. It seems yellowing stopped.
Lighting ok as Zoa corals open up in response. Color of Zoa were ok.
Introduced 2 scarlet hermit

On 3rd day
It seems some 2 small bunches of grape were ok. Zoa corals remain strong.
Other long time inhabitants, scarlet hermits and cleaner (yellow and red) are ok. Of course the fishes are ok.

Question: what caused the grape caulerpa to turn yellow, soften and died?
These were eaten up by 2 scarlet hermit which were introduced 2300hr 2nd day. Is it the iodine or the sorb-4, phoshate remover introduced on evening of day 1.

:confused: :mixed:

[graveyardworm]

Did you acclimate the Caulerpa to the new tank water? What was the SG of your water and of the water the Caulerpa came in? What was the source for the Caulerpa, and did it have to be shipped to you?

[BengBear]

Hi,
The grape were obtain from fellow reefer, who grow the grape. I did not acclimate the grape, as this is the first time handling grape. My tank sg was around 1.022 but not sure with the water the grape came with.

What is the acclimate time comfortable for grape?

For my info, what is most concerning parameter(s) to new grape added to main tank?

[AnOldSalt]

For whatever it may be worth, I've often found large grape to be nearly unstoppable, but small grape to be very delicate and prone to withering after transplant. It usually springs back again after it acclimates.

[BengBear]

Yes, I believe mine is small grape or grape caulerpa remorsa. There many new shots and roots growing from the small bunch of grape.

Is magnesium helping its growth? Very tempted to add more to somewhere more than 1300ppm.

Also very tempted to buy large grapes to bring down nitrates hovering 20 plus ppm. But apprehensive with the unstoppable growth mention by AnOldSalt. I think the 3 angelfish in the tank with finish them in no time, once release from the beta box, which is holding place of existing small grapes.

[BengBear]

Since the small caulerpa racemorsa are growing healthily in the beta box of the main tank and I intend to change about 20% water.

From experience, the saltwater mixed from RO/DI will have some different water quality, KH, Calcium, magnesium.

Please comment whether the new water quality should be brought near to what is in the main tank, just to avoid killing the growing caulerpa.

[graveyardworm]

As long as SG, pH, and temp match closely you shouldnt have any worries with the Caulerpa. For more sensative inverts though like corals you should also match your Ca, Mg, and Alk. My saltmix is generally low on these three so I buffer it up to match before doing my water change.

[BengBear]

Thanx,
Changing 20% water this weekend to bring down nitrates since there are some scarlet hermit, snails, anemone and zoa in tank. Nitrates should be hovering around plus 20ppm.

Hope to give some time for caulerpa to grow and subsequently be a good nitrate removal and cut down water change.