Hi
I've recently bought a normal spotlight for my 2 1/2 ft tank. Just trying out the effects of this light. It is MH 70W 6500K. Don't know if it will work when I buy it but plan to use it as light for photo session if fail as an aquarium light.

Anyways, my initial impression is, wow. This light is bright. Water ripple effect from this light is very nice. My glosso (new tank) is growing horizontal very fast.

However, 1 week observation comparing with my PL36W is:-
1) MH70W is more like afternoon sun with harsh shadows. PL is very nice diffused light.
2) Fish color is wash out using in MH70W. Boraras which is redish previously using PL looks brownish using MH. So does the color of plants.
3) Heat is ok using PL and MH. Both achieving 25C-26C nowadays. In fact, my PL tank (2ft X 2) is 26.5 using 1 AC fan. My MH (2 1/2 ft X 1 tank) is 25.5 using 1 AC fan and 2 medium size DC fan.
4) Plant seems to be bubbling. So, I guess they are growing.
5) A lot of shadows (unlited areas) using MH. However, non-shadow areas are brighter.
6) Gold tetra is one nice fish in MH lighted tank. Looks like shimmering stars from afar because of the reflected lights. I think fishes with shining body is very effective in MH lighted tanks. So maybe rosy barb would be nice too.

Summarized impression:
MH70W X 1 gives afternoon sun effect but ripple effect is fantastic.
PL36W X 4 gives softer studio like effect.

Will appreciate anyone to comment on the usage of MH and their experienced so we can learn from each other. Perhaps can help list down other shiny fishes as well.

Wow..that is a good comments from you. Mind to let us know what is the distance you hang your MH and the water level? And where you bought yr MH? Brand? And what price?

I am planning to get 2 MH for my 4ft and running together with my FL. Your comments is good enough for me to get it... Btw, the lighting color is white or warm white which is yellowish?

Hi Dom

My aquarium is the regular 2 1/2 ft aquarium. So, height is about 15-18 inch if I remember correctly.

Height of MH is approximately 1 ft +- from water level.

The whole set is about RM180+-. Maybe can have better price in Pasar Road. It is those regular black box spot light seen everywhere. Brand of light (not casing) is venture lighting if I remember correctly. They have a website http://www.venturelighting.com/. The bulb specs is here

It is white light. To my eyes, it is a bit blue but hard to see as it is very bright. I believe the shop have another brand but color is 5500K. Osram if I remember correctly. These are 70W, perhaps 150W will have more color variety.

I think your idea is a good one. Having MH penetrate and give ripple effect and florensent to give diffused/reflected light. Would it be too much light though?

The shop is in Paramount. You know Giant. There is a fish shop around, Yee Fatt I think. A few shops from that is this light shop.

BTW. The ignitor, ballast, ... etc is external. Not so hot nor heavy.

cool, good on you for great comments and contact. have me sold... esp since only 70w

__________________
So many aquascapes, so little time...http://www.my-mac.net/forum/

Heh heh... not trying to sell this light. Guess not tested yet is the durability.

Coming from previous FL/PL light, I tend to like PL for eye pleasing aquascape. MH simply washes out the nice colors of fish and plant. That's why I mention that shiny fish is effective but probably not color fish for short tank like mine.

I'll probably visit ytlim with MH to view how his MH look like again. He have a deep tank.

A good compromise would probably be what Dom is planning to do, mix with FL. In fact, from what I read, Amano recommends lighting with MH only 4 hours, the rest of the day with PL or isit FL. I believe he also recommends dosing CO2 during MH.

The benefit is :
1) lower growth late = lesser maintenance
2) lesser algae
3) lesser CO2 usage
4) electricity saving

Let me try to take a picture of the tank to let you see what I mean.

I've been looking for a 6500 K MH but have not managed to find any so far. Thanks for the info. I've previously bought a 250 W MH set from Jalan Pasar (to light up my garden) but that had a locally manufactured ballast and the Philips lamp was only 4200K. Of course, 250 W for garden lighting is overkill... and it's not much use for 'security' purposes because it takes so long to power up...

If I'm not mistaken, there are a few lighting shops along that row of shops... is the shop on the left or on the right of the LFS if you are facing the LFS?

How did you mount the light? MH ballasts are kind of heavy... A picture of your setup would be appreciated. I guess with all the heat generated, it would be a bad idea to mount it in the hood although the marine people do it all the time...

Any idea how often we need to replace MH bulbs (every 6 months or so for fluorescents although the rated lamp life is much longer) and the cost of the bulb itself?

Thanks.

Here is a quick photo for comparison. Sorry about the quality but it is just to compare the effects of both. Notice the algae colour looks greener on PL.

MH Light - MH70W X 1


PL Light - PL 36W X 4


NOTE: Photo doesn't show the effects of gold tetra which IMHO is nicer on MH. Also, I've notice while taking picture that if I stop the ripple, MH colours up a littler nicer.

BTW. This tank is my aquascape, algae propagator (yes I am propagating the algae), moss propagator and temporary fish storage. The MH(1 week old) also did not cause the algae. I took it from another tank and tied to driftwood here.

hi cj,

do you perceive the mh to be yellower than pl? i mean with your eyes and not camera pix. [because the white balance of camera may not be calibrated...]

__________________
So many aquascapes, so little time...http://www.my-mac.net/forum/

Hi Ruslan
Thanks for your post. Just to answer as best I can.

If I remember correctly, it is the shop to the right when you are facing the LFS. Just look inside, the shop have lots of different lights hanging down their ceiling.

I hang it off a PVC rack. It is not ideal as it is not very stable. I am changing it as soon as I get materials to hang off the ceiling. Hang using chains.

BTW. Ballast, ignitor are all on the external box. You can see a white box at the back of the aquarium. This is so that light casing lighter and not so hot.

The reason temperature is not so high is because the aquarium is open top. The rainy season help a lot as well. This tank is outdoor.

I guess being non-electronic ballast(which cost a bomb I heard), life span may be shorter. I don't really know how good the lamp is in the long run but my guess is if it gets dimmer, it is still enough light for some time.

Cost of bulb, I think about RM70. Have to ask the shop for a more accurate answer as I did not pay attention when shopowner told me the price. It is about that range though.

Right now, my perception is MH whiter than PL. However, 2 of my PL tube is a bit old and could cause it to be abit yellowish. The picture is using same shuttle speed, aperture and white balance. White balance is auto though.

The MH(new) is quite similar to what you see at Melvin's place.

BTW. I psycho him to put some gold tetra in his tank...