# Deep Tank getting high light levels



## SamH (Jun 10, 2010)

Hi, 

I'm new to this forum, but i currently have a planted tank with prodominately Australian Native Plants eg, rotala occultiflora, limnophila aromatica & fragrans, pogostemon stellata and hygrophila augustifolia. 

My Tank is 48'L x 24'W x 28'D. I have 4x 54w t5 fluro's and 2 x 150 w metal halides. I was wondering whether i need to upgrade my wattage 250w higher? I'm wanting to know because my rotala is about occultiflora is roughly 10cm/ 4 inches high and about 2.5ft from the halide, and only has leaves around the top end, and a darkened stem. My pogostemon also grows slow and looks leggy and drab. 

I reguarly dose an EI regime using dry ferts csm+b etc... and co2 is normally between 20-30ppm.
My Halides are on for roughly 6 hrs while the t5's are on for 10-12.

Any advice is greatly appreciated.

Cheers
Sam
Australia


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## Seattle_Aquarist (Mar 7, 2008)

Hi Sam,

First of all I see you are a new member, welcome to APC! It looks like you have sufficient light, do you know what the fluorescent bulbs K rating is? Also for the MH bulbs?

I have a tank that is 24" deep, and it can be difficult to get good light down to the lower level. Do your fluorescent bulbs have individual reflectors in the fixture?

Since you are dosing your ferts per EI I will assume that is OK for now. How do you check you CO2 PPM? If a drop checker do you use 4.0 dKH water with the indicator solution?

Also, current water parameters would help. dKH; dGH; NKP, etc.


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## SamH (Jun 10, 2010)

My MH is an 8000k solarmax bulb 150w
the t5 fluros are; 1 sylvannia grolux doesn't give k, but has high blue and red
1 powerglo 18000k high blue red green spec
1 aqua/life glo 6700k
1 solarmax 1100k midday

I noticed that some plants grow leggy and the bottom leaves can fall of at the stem, only in smaller youg plants eg rotala occultiflora and pogostemon stellata. 

Kh and gh are both around 50ppm, I measure co2 with a drop checker and the sera thing that sits in the tank. Ph is around 6.8-7.0 I use a clay and organis fertilser root ball for aquariums


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## SamH (Jun 10, 2010)

Hi so has anyone got ideas on how to improve light to deep tanks?

I use solarmax 8000k globes, is anyone aware of globes that have more equal levels of blue and red spectrums?

Is anyone familiar with venture 6000k globes?

Any feedback would be appreciated.

Sam


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## Seattle_Aquarist (Mar 7, 2008)

Hi SamH,

I apologize, I lost track of this thread! I still think you have sufficient wattage.

Where are the lights located? Are they located at the tank top or above the tank but a substantial distance. Here is a thread that I am researching that may help you substantially.

First, I would replace any bulbs that are over 1 year old since they degrade with time, cycles, and use. I would replace the 18000K bulb with a 6700K (Daylight) and probably the Gro-Lux with 6700K as well. I have used Gro-Lux in the past myself and I also had problems with leggy growth. Bulbs in the 5000K to 10000K are typically used with planted aquariums.

I'm not sure you answered my question on CO2, do you use 4.0 dKH water with your indicator solution in the drop checker? Otherwise it is likely the CO2 concentration reading is wrong and this will certainly effect growth.

I think I would make sure the existing equipment is providing maximum PAR in the proper spectrum before spending money on more light.


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## SamH (Jun 10, 2010)

My lights are located above the top of the tank about 20cm... under 1ft? I might fo that as i'm starting to think i have way too much light and that it's probably not my problem and i'm more leaning toward a co2 problem. The c02 drop test kit uses 2 regent drop bottles. I'm unaware of what dkh 4.0 means, but i couldn't find it on the packaging? If your talking about kH hardness? Its around 50ppm in my tank?

I use 2 DIY Soda bottle generators for my tank so i'm now assuming that this isn't an adequate supply of c02.
Any info on a simple c02 pressurised systems for a beginner will be greatly appreciated.

Cheers
Samh


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## Seattle_Aquarist (Mar 7, 2008)

Hi SamH,

Yes, 4.0 dkH refers to the hardness. Typically here we use 2 - 6 drops of bromthymol blue in a drop checker filled 1/2 way with 4.0 dkH distilled water.

I think you are on your way to solving your problem; insufficient CO2. I estimate your tank at 120 U.S. gallons. When I started I did DIY CO2 and used 2 each 2 liter bottles on my 45 gallon and it was inadequate with only 2 watts per gallon of lighting.

I constantly have to remind myself that my aquarium is a "system" where the light, carbon, and nutrients have to be in balance. Usually I have problems when I try to boost or cut back one part of the equation without adjusting the other two.

I would still consider my bulb selection. I would immediately cut back my photoperiod by 1/2 (both T5's and MH), leave ferts the same, and see if growth shows some improvement. If you can add additional CO2, either more DIY or pressurized, I would do so.

Let us know how things progress!


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## houseofcards (Feb 16, 2005)

I think Seattle gave you some really good advise regardless of which plants you have, but if I'm reading you correctly your lights are about 36" from the bottom of the tank. Most of those plants you have listed require intense light to get them to grow their best. With your height tank that's extremely difficult to do. I don't think even the 250MH will drive enough light to get them to 'really grow' the way you want them to.


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## Tex Gal (Nov 1, 2007)

I'm wondering if there is any way you can introduce some light from the sides for these deep tank. Maybe it could be done with a tube placed half way down the tank in the back. Of course, this assumes that some of this light would seep through to the front of the tank. It is possible that it could cause odd directional growth patterns, but maybe not as long as the strongest light comes from the top.


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## SamH (Jun 10, 2010)

Thanks for the input Tom Barr suggested I have way to much light regardless of my depth, that he has same dimensions as my tank and powers only 4 t5 ho tubes. I think my problem is co2.


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## Seattle_Aquarist (Mar 7, 2008)

Hi SamH,

Keep us posted on how things progress, we are glad to have helped.


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## houseofcards (Feb 16, 2005)

SamH said:


> Thanks for the input Tom Barr suggested I have way to much light regardless of my depth, that he has same dimensions as my tank and powers only 4 t5 ho tubes. I think my problem is co2.


It's possible to grow plants at that depth, but not with those species. I actually setup a tank that was 36" deep and the lights were anotehr 10" on top and I grow many types of plants. But to grow for example L. Aromatica and get good color, etc I havent' seen that at those heights.


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## JERP (Feb 4, 2003)

I'm a big fan of tall tanks, provided you can reach the bottom for maintenance. 

The two biggest problems one has with tall tanks is water clarity and water movement. Without good water clarity you'll have a tremendous amount of light loss at depth. Without good, even water movement, you'll have stagnant cold spots that cause stem rot and localized bba/bga outbreaks. You don't need high current, you just need to know that nutrients and warm water are reaching all areas. Dosing doesn't matter if the nutrients never reached the plant due to poor circulation. 

You can grow light sensitive plants in a tall tank, but maintaining the necessary stability is more difficult and sometimes not worth it. The margin of error is small.


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