seagrass turning brown

[andycook]

I have 12 seagrass plants (Thalassia testudinum) in my display tank. The end several inches on most turn brown. Is this normal or is the tank lacking nutrients, iron, or lighting too low?

The tank is a standard 180 (72"x24"x24") that has been running for 6 months. I have 760W of VHO light on for 12 hours which virtually rest on the tank top. The tank has a 6" DSB. Half of that sand came from a prior setup and half was added when the tank was started this past February.

Thoughts?

 

[hmott]

I can't add anything in the way of help for you, but I can tell you I also have 10 plants and they do the same thing. I have them in about 5'' of sand and I dose iron once a week. My lighting is 130w of 50/50 over a 55g tank. I assumed my problem was lighting thats to low but now that I see you have 760 over a 180 with the same issue maybe lighting is not the problem. I get a new leaf and after its about 6'' tall it starts turning brown.

 

[andycook]

Hi hmott;

I had a different batch of seagrass in a 75 gallon tank last year. Those did the same thing when I had them under dual 175W MH. The seagrass in this tank didn't make it when transplanted from this tank to the 180 so I had to start again.

Is it seasonal? I've had this batch of seagrass in the 180 for 4-ish months.

Are you dosing liquid iron? Does your skimmer go crazy? I was considering plant spikes or root tabs to dose the iron or even putting laterite in the tank.

My sandbed is a mix newer sand with sand from my previous tank so I though I had a mucky enough sandbed to make the plants happy. Two of the 12 plants are new starts so the seagrass isn't completely unhappy.

Do you trim the brown sections or wait till they break off and get them then?

-Andy

 

[hmott]

I'm not sure if its seasonal or not, I've only had mine a little over 2 months now.

I am dosing liquid iron by kent (iron and magnesium I believe). I don't run a skimmer, this is a seahorse tank and skimmers are believed to cause a fatal disease in seahorses (internal gas bubble disease) so I don't use one. I've also thought about adding plant spikes or even freshwater plant additives, and fw laterite but I don't want to be the first one to do any of that I also am not sure I want to be the first one to try it with seahorses.

My sandbed was also about 50/50 new and old and I added all the new LS over the old hoping that might kill off some more stuff that could be food for the grasses. I've noticed if I pull out a piece of macro thats rooted by the seagrasses the sand looks black below the surface, but I have no idea if this is good or not.

I don't have any new starts, I was under the impression that it would grow flowers and drop seeds? You had that happen?

I haven't been trimming the brown sections, I've been waiting for them to break off. I even thought about pushing them into the sand but I haven't had the courage to do that for fear of messing with my sandbed. So far I've just tossed them out when they fall off.

 

[andycook]

Do a search here on laterite and see what you think.

I haven't had any flower but I've had them spread through their root system.

I stir my sandbed so I can't spead for black sand.

Brown is dead.

 

[billsreef]

Typically the older leaves start browning from the dips and eventually die and fall off. However, while this is happening you should be seeing new growth coming up to replace the old growth. If your not seeing new growth, than I would try supplementing iron and looking into fertilizer tabs. For the fertilizer tabs I'd go with either the ones sold for FW plant tanks or Job's spikes from a garden supply store. The Job's spikes are the only one's I've seen that don't include copper as an ingredient, so if your looking at others be very carefull in reading the ingredients

 

[andycook]

Thanks Bill. I should have said that the brown is always replaced by new growth. Since they are dead, any harm in trimming?

 

[billsreef]

No problem trimming the old growth

 

[Plantbrain]

It's not the lighting, I have less and grew the damn grasses too fast, they started growing like mad. I had to trim them like hair.

The DBS needs some Organic matter or a jobes will work also, I dount you'll do much uprooting or have diggers that might uproot a jobes.

I've used Grey coast Calcite with very good results and added some potting soil that's been soaked.

You can add Orangic matter easily to an existing tank, add some water to dirt, => mud, add this to an ice cube tray. Take the frozen mud cubes out and push under the plants.

Also, these plants like aeration/current, Ca, alkalinity and NO3 etc.
Plants will take from the substrate generally when the water column is limiting, otherwise they will go after the water column nutrients first.

I've never added a jobes to a seagrass as Bill has, I used soil instead, but it should work just dandy also.

But die back on the tips is common, new growth will take sometime to get going, but when it does, they will grow quite fast.

Regards,
Tom Barr

 

[Fredfish]

add some water to dirt, => mud, add this to an ice cube tray. Take the frozen mud cubes out and push under the plants.

Oooh, thats so clever. All those years I kept fresh water plant tanks and I never thought of freeziing mug!

Fred.