Making the transition 't5 to MH'

[andyh]

Hello

My new Metal Halide arrives in a few weeks and want to start to think about the transition from my current lights Arcadia 60cm Luminaire 4 x24w T5 tubes for 7 hours per day. The main reason for the change was the fact that the 6Ocm light was a tempoary fix whilst waiting for Mh to arrive from Japan.

Tank spec is 190l (90cmx45cmx45cm)using pressuirzed CO2,(green drop checker by lights on) dosing daily ADA nutrients (step1 and brighty K) and an amazonia/powersand special substrate. The tank will be a couple of months old when the light arrives, so fairly stable/mature with good plant growth. See my lounge tank journal in my signature for more info

So in short I will be moving from 96w of light to mh150w light.

I think i know some of the answers, but would be interested in what advice/experience you can give?

Thanks

Andyh

 

[Dan Crawford]

Quite an obvious one, which you've no doubt already thought of is to double the hight in which you suspend the light above the tank. You're not far off doubling the light intensity with 150w of halide so if you start off twice as high, keep an eye on the CO2 and slowly bring the light closer to the surface if you feel you need more then you'll be sound as a round pound

 

[andyh]

Quite an obvious one, which you've no doubt already thought of is to double the hight in which you suspend the light above the tank. You're not far off doubling the light intensity with 150w of halide so if you start off twice as high, keep an eye on the CO2 and slowly bring the light closer to the surface if you feel you need more then you'll be sound as a round pound

Cheers Dan

So no 1 Raise the light and keep an eye on C02

What about nutrients as the plants will be getting more light is it advisable to increase the dosing slowly etc

Should i reduce the photo period from say 7 to 6 hrs? will that help?

 

[Dan Crawford]

What about nutrients as the plants will be getting more light is it advisable to increase the dosing slowly etc

hmm, well, in theory, as you've raised the lighting the levels are similar to what you had previously. As you lower the light you may need to up the nutrient levels, you will have to up the CO2. A small amount of trial and error will be required but CO2 is key IMO. Your plants will let you know if they are struggling a bit for food, algae will let you know if the plants are struggling for CO2!

Should i reduce the photo period from say 7 to 6 hrs? will that help?

As i say above, since the lighting levels are similar to your previous setup, you shouldn't need to drop the photoperiod. Once the tank gets used to the halide and you lower it slowly it should be quite an easy transition for the plants.

Mine currently sits about 40cm above the surface - over 200l, i'm thinking of lifting it up a bit as recently i've not been so up on my maintenance

 

[Garuf]

If there's no animals in the tank I'd say it's prudent to up the light as you change over, you're safe gaurding against any changes that way because your co2 could/should be higher than needed.

 

[Stu Worrall]

i had the same problem andy going from 96W to 150w with mine. As dan has said I raised the level of the light (about 35cm) and upped the co2 and ferts. it all went smoothly and i think i may have doubled up on the water changes for two weeks after to be sure.

 

[andyh]

All sound advice chaps! Thats why UKAPS rocks.

Just good to check!