Lighting questions - Metal Halide

[CleverBs]

Alright so I have been in the saltwater reef hobby for a few years now and I am at a time in my life where I want to go back to planted tanks for a bit and take a break from reefs.

here is my questions. right now I have two tanks. one tank is a 30g cube that has a 250w MH over it that I want to do a full planted hightech tank I am assuming from the past that 250w mh will be more then enough light my worry is is it to much?

other question is I have the same situation over my 220g tank. I am not going to do a full blown planted tank on the 220g because its going to be a amazon biotope and will have a group of Geophagus. However I want to have some plants in it. The lighting on this tank is 3x 250w MH and 4x 6ft t5ho's

 

[Delapool]

Alright so I have been in the saltwater reef hobby for a few years now and I am at a time in my life where I want to go back to planted tanks for a bit and take a break from reefs.

here is my questions. right now I have two tanks. one tank is a 30g cube that has a 250w MH over it that I want to do a full planted hightech tank I am assuming from the past that 250w mh will be more then enough light my worry is is it to much?

other question is I have the same situation over my 220g tank. I am not going to do a full blown planted tank on the 220g because its going to be a amazon biotope and will have a group of Geophagus. However I want to have some plants in it. The lighting on this tank is 3x 250w MH and 4x 6ft t5ho's

I'll have a stab at this but new to lighting.

Particularly on the 30 gal I'd say you have more than enough and may have trouble keeping ferts and co2 up to it. The other issue may be that the lights you have now won't suit planted tanks (different spectrum).

On my 150gal I run a 4ft quad t5ho which is said to be enough. However tank is 2.5ft deep so I suspect I could run another 2 bulbs without issues. I use two white light bulbs and two red light bulbs. Dry dose ferts plus glut and co2 injection.

Before that:

The LEDs I had were 2 x box 250w (blue and white) on outside and a centre 300-400w (reds). I never noticed anything that looked like burnt leaves.

I ended up running the outside boxes with blue off (just white light) so really 2 x 125w and for 6 to 8 hours per day.

The centre light (reds) I dropped down to 4 to 6 hrs a day. This light was too strong even with the poor light penetration reds light has. The hygro constantly had potassium deficiency unless I overdosed above EI levels and I had to keep co2 (as well as glut dosing) up to it.

When it all worked though, the plants had great growth rates. Then I got sick of the plant trimming and fighting BBA and cut the hours down.

So if you are able to remove bulbs / dim? (never had MHs) you could always try them and adjust lighting to suit. I would suspect it would be down rather than up but just my thoughts and interested from the experts.

 

[CleverBs]

I'll have a stab at this but new to lighting.

Particularly on the 30 gal I'd say you have more than enough and may have trouble keeping ferts and co2 up to it. The other issue may be that the lights you have now won't suit planted tanks (different spectrum).

On my 150gal I run a 4ft quad t5ho which is said to be enough. However tank is 2.5ft deep so I suspect I could run another 2 bulbs without issues. I use two white light bulbs and two red light bulbs. Dry dose ferts plus glut and co2 injection.

Before that:

The LEDs I had were 2 x box 250w (blue and white) on outside and a centre 300-400w (reds). I never noticed anything that looked like burnt leaves.

I ended up running the outside boxes with blue off (just white light) so really 2 x 125w and for 6 to 8 hours per day.

The centre light (reds) I dropped down to 4 to 6 hrs a day. This light was too strong even with the poor light penetration reds light has. The hygro constantly had potassium deficiency unless I overdosed above EI levels and I had to keep co2 (as well as glut dosing) up to it.

When it all worked though, the plants had great growth rates. Then I got sick of the plant trimming and fighting BBA and cut the hours down.

So if you are able to remove bulbs / dim? (never had MHs) you could always try them and adjust lighting to suit. I would suspect it would be down rather than up but just my thoughts and interested from the experts.

Well yes right now the bulbs in the MH are for reef tanks so they are very blue 18-20k so no they would not be used for plants I would just replace the bulbs and the nice this about plant bulbs is they are MUCH cheaper then the high end reef bulbs. For the 220g I am no longer worried about it because Im not going to keep much for plants in that tank Maybe just a couple big swords or something so the 4 t5hos should be fine for that.

My main concern was if a 250w MH with a 7500k bulb in it was going to be to much but I dont see how it could be and I can raise and lower it as much as I want. Honestly I am not 100% sure why I asked the question in the first place haha

Just want to say in regards to the CO2 and ferts I am going to try something a bit different that I have never done before with a planted tank.

The 30g is connected to the 220g because it used to be my Frag tank so the whole system is tied together. I was thinking of leaving them connected and co2 dosing and fert dosing the whole 280ish gallons. This should keep my fert levels from swinging up and down and same with the co2. The co2 will be good for the amazon tank as well as it will keep the PH down for the fish that are in it. This will also allow me to not have a heater or anything in that tank because I can keep it all in my sump so there wont be any cords or anything in the planted tank keeping it really nice and clean.

I also used to dose calc alk mag with a doser pump and I was thinking of using it with ferts however I dont know if I will ever need that much fert in just 30gs to justify it and may just does manually

 

[aqua_chem]

So are you going to plumb them together or not? I'm not sure that there would be any advantage from putting them together, especially if you're going in different directions with them, ie, one's going high light/high tech, the other less so.

For the 30g, I would think that a MH would be overkill for basically anything FW that you wanted to do with it. Yes, you probably could raise it quite a bit, or even run it right over the tank, but there's a serious question here about should you. To me, it would unnecessarily complicate the tank, and will likely lead you to a frustrating and unnecessary series of algae/plant battles. A lesser lighting system might be warranted, and there are many good and economic alternatives available these days. Remember, in FW, bigger is usually not better; it's just more complicated and subject to diminishing returns.

For the 220:

I am no longer worried about it because Im not going to keep much for plants in that tank Maybe just a couple big swords or something so the 4 t5hos should be fine for that.

This is probably the correct sentiment, although 4xT5HO is still a good amount of light for any tank. While the depth of the tank will markedly reduce light levels at the bottom, it's important to remember that swords are very tall plants, and the tops will be subjected to pretty high levels of light. I would say there's not much harm in trying with 4x bulbs, but be prepared to either reduce it to 2x or use some other method to reduce light.

Of course, if these is a decent fixture and these are quality reflectors as you often find on some SW tanks, you might have problems regardless. Just something to keep in mind.

 

[CleverBs]

They are very high quality fixtures. I can always just run two t5hos over the 220g. The reason they are together is because they are already plumbed together because of how the system was set up before. Undoing it is imo not worth it just because I'd have to re plumb the 220g and cut some drywall as well as buy a heater and filter for the 30g. I think what I'll do with the 30g is change it to a 175w and see how that goes. I forgot it's ballast has a switch that lets me just change the watts and I'll need to buy a different bulb anyways beings the one that is running in it now is old and 20k

 

[Delapool]

While looking for something else I did come across this lighting chart.

My tank height is 30 inches plus lights are 4 inches above top (plus I have perspex covers which aren't as clear as glass and also not great reflectors on lights). This might be why I'm not seeing some pearling anymore.

Tips for a Successful Planted Aquarium - Aquarium Fish Forum

 

[CleverBs]

While looking for something else I did come across this lighting chart.

My tank height is 30 inches plus lights are 4 inches above top (plus I have perspex covers which aren't as clear as glass and also not great reflectors on lights). This might be why I'm not seeing some pearling anymore.

Tips for a Successful Planted Aquarium - Aquarium Fish Forum

well based on this chart 4 bulbs looks like it will be good for my t5hos tank is 30" deep and the lights are about 10" off the top of the tank.