Controllable deep sand beds - a discussion thread

[Lasse]

I use a GHL Profilux with 32 inbuilt timers

Sincerely Lasse

 

[Val Shebeko]

What happened with the Dimico?

Nothing with Dimico. The new owner is on vacation, yadda yadda.

Sticking with water changes and disconnecting ever more dosing pumps and chems. At this rate I’ll be ablevto save enough to vacation in Hawaii.

 

[Mortie31]

To resurrect this thread, and ask a question of you all; in a few months I’ll be adding a 4x2x2 tank (400L) into my existing 800L system, they will share a sump. This new tank will be in a new direction for me with soft corals, NPS? algae’s, sponges, pipefish and other slow living fish. More of a display Refugium I guess, the point of posting in this thread, is I’m considering a reverse deep sand bed about 6” deep and along the lines of @Lasse utilised in his tank, the main diference will be it will be in this new tank. I will create a plenum under the dsb and t off from the return pump to constantly feed the plenum, the amount of flow can be varied, I may put a GHL redox probe down into the plenum to monitor (can they be entirely submerged indefinitely?) I am concerned about the size and efficiency being to high. Any thoughts or suggestions? @Sallstrom @Subsea

 

[Lasse]

(can they be entirely submerged indefinitely?)

They say no - but I have done it many times without any problems at all. For the moment I run my pump (pumping into the plenum) with a pH meter submerged into the plenum. It uses a variable nominated value and my pH in my tank is that parameter. I try to have the pH below the DSB as the same as my open water pH – if I do not pump in any water from the refugium – the pH will decrease in the bottom of the DSB.

Sincerely Lasse

 

[Mortie31]

They say no - but I have done it many times without any problems at all. For the moment I run my pump (pumping into the plenum) with a pH meter submerged into the plenum. It uses a variable nominated value and my pH in my tank is that parameter. I try to have the pH below the DSB as the same as my open water pH – if I do not pump in any water from the refugium – the pH will decrease in the bottom of the DSB.

Sincerely Lasse

Thanks @Lasse do you now measure ph rather than redox in the plenum?

 

[Dr. Dendrostein]

To resurrect this thread, and ask a question of you all; in a few months I’ll be adding a 4x2x2 tank (400L) into my existing 800L system, they will share a sump. This new tank will be in a new direction for me with soft corals, NPS? algae’s, sponges, pipefish and other slow living fish. More of a display Refugium I guess, the point of posting in this thread, is I’m considering a reverse deep sand bed about 6” deep and along the lines of @Lasse utilised in his tank, the main diference will be it will be in this new tank. I will create a plenum under the dsb and t off from the return pump to constantly feed the plenum, the amount of flow can be varied, I may put a GHL redox probe down into the plenum to monitor (can they be entirely submerged indefinitely?) I am concerned about the size and efficiency being to high. Any thoughts or suggestions? @Sallstrom @Subsea

We'll be following.

 

[Lasse]

I measure both but I try to regulate both DOC addition and Redox level below the plenum but get a lot of upp and down - around 100 mV. The other day I figure out that I can use GHL dynamic nominal value to maintain the same pH below the plenum and in open water. When pH rise in the day (in the DT - the dynamic nominal value will have the pump to pump more into the plenum. Next step is to use a fix addition of DOC down to the plenum and see whats happen.

The graph show how well it will follow. The thorny line is the pH below the DSB - it is torny because the pump works in interwals in order to get the same pH as in the DT. Normally the pH will decline in the plenum if not new water with higher pH is pumped in. It will be a little different if I get a real denitrification in the plenum.

Sincerely Lasse

 

[Subsea]

To resurrect this thread, and ask a question of you all; in a few months I’ll be adding a 4x2x2 tank (400L) into my existing 800L system, they will share a sump. This new tank will be in a new direction for me with soft corals, NPS? algae’s, sponges, pipefish and other slow living fish. More of a display Refugium I guess, the point of posting in this thread, is I’m considering a reverse deep sand bed about 6” deep and along the lines of @Lasse utilised in his tank, the main diference will be it will be in this new tank. I will create a plenum under the dsb and t off from the return pump to constantly feed the plenum, the amount of flow can be varied, I may put a GHL redox probe down into the plenum to monitor (can they be entirely submerged indefinitely?) I am concerned about the size and efficiency being to high. Any thoughts or suggestions? @Sallstrom @Subsea

When I converted to reverse flow ug filter, I removed a dsb with Jaubert plenum that I operated for 25 years. It worked well for denitrification of nitrate to export free nitrogen gas. As the tank matured, I had to add nitrogen and feed the tank heavily.

I prefer 2” aroggonite sandbed with reverse flow ug filter.

 

[Mortie31]

When I converted to reverse flow ug filter, I removed a dsb with Jaubert plenum that I operated for 25 years. It worked well for denitrification of nitrate to export free nitrogen gas. As the tank matured, I had to add nitrogen and feed the tank heavily.

I prefer 2” aroggonite sandbed with reverse flow ug filter.

Thanks Subsea, I’m glad you have tried both ways, what are your thoughts on a 5-6inch sand bed with reverse flow ug filter, will it be too deep?

 

[Mortie31]

I measure both but I try to regulate both DOC addition and Redox level below the plenum but get a lot of upp and down - around 100 mV. The other day I figure out that I can use GHL dynamic nominal value to maintain the same pH below the plenum and in open water. When pH rise in the day (in the DT - the dynamic nominal value will have the pump to pump more into the plenum. Next step is to use a fix addition of DOC down to the plenum and see whats happen.

The graph show how well it will follow. The thorny line is the pH below the DSB - it is torny because the pump works in interwals in order to get the same pH as in the DT. Normally the pH will decline in the plenum if not new water with higher pH is pumped in. It will be a little different if I get a real denitrification in the plenum.

Sincerely Lasse

Thanks @Lasse I think I understand what your trying to control with ph, do you use a 1-10v pump controller on your ghl system to react to the ph?

 

[Subsea]

Thanks Subsea, I’m glad you have tried both ways, what are your thoughts on a 5-6inch sand bed with reverse flow ug filter, will it be too deep?

I am sure they both will work. I see the extra depth > 2” as an unnecessary complication.

 

[Mortie31]

I am sure they both will work. I see the extra depth > 2” as an unnecessary complication.

Thanks, what flow do you run through your ug filter?

 

[Subsea]

250GPHR. WITH 6 sq ft of footprint

 

[Lasse]

No 1-10 V is only on-off. I have asked them to ad a controller function for the pH as they have done for temp and chilling by a fan.

Sincerely Lasse

 

[Dennis Cartier]

I have some news about my plans for this type of filter. I posted earlier showing the 'guts' of a DIY version of a DyMiCo filter that I had underway. As it were, plans change. I decided I wanted a more polished sump rather than a bunch of individual parts lumped together. With that in mind I have designed and ordered a custom sump incorporating my take on the DyMiCo style of filter, or a controllable sand bed depending on your perspective. The fabrication has not started yet, so I thought I would post the plans here to get feedback.

The sump is 8' long, 26" wide and 21.5" deep. It will be constructed out of 1/2" PVC. The sump portion consists of 3 chambers (overflow, equipment, return) and occupy about 40% of the 8' length. The other 60% is the DyMiCo filter.

Here are some screen grabs of the model. This is not final, but is what has been provided to the fabricator for rough guidance. The tall cylinder is a placeholder for the dimensions of the skimmer I intend to use, as are the black rectangles for the pump foot prints.

A spray bar is positioned above the sand bed (red pipes). The media bed has 7 pipes running through it. The top layer is 3 feed pipes and the bottom has 4 return pipes.

The sand bed will be supported on a perforated PVC sheet incorporating some standoffs to support the spray bar. The plan is to have about 2" of water above the sand bed under normal operation.

The water levels are intended to allow either a small passive flow through the filter, or with the addition of a manifold and stand pipe, an active pumped flow, that can be controlled using float switches and pumps in the overflow chamber and filter return chamber. The return line from the filter bypasses the equipment chamber and discharges directly into the return chamber to (hopefully) preserve the zoo plankton from the filter.

I purchased enough Reborn media in advance to fill the bottom media compartment, but now I am thinking of using Pond Matrix instead and saving the Reborn for use in my CalRx. I have an A.E. ACR CalRx on hand that I will be using for supplementation, so I will not be using the media bed for that aspect. Besides, Reborn is so hard to get hold of these days, I should probably reserve it for CalRx use instead.

Let me know what you think.

Dennis

 

[Mortie31]

I have some news about my plans for this type of filter. I posted earlier showing the 'guts' of a DIY version of a DyMiCo filter that I had underway. As it were, plans change. I decided I wanted a more polished sump rather than a bunch of individual parts lumped together. With that in mind I have designed and ordered a custom sump incorporating my take on the DyMiCo style of filter, or a controllable sand bed depending on your perspective. The fabrication has not started yet, so I thought I would post the plans here to get feedback.

The sump is 8' long, 26" wide and 21.5" deep. It will be constructed out of 1/2" PVC. The sump portion consists of 3 chambers (overflow, equipment, return) and occupy about 40% of the 8' length. The other 60% is the DyMiCo filter.

Here are some screen grabs of the model. This is not final, but is what has been provided to the fabricator for rough guidance. The tall cylinder is a placeholder for the dimensions of the skimmer I intend to use, as are the black rectangles for the pump foot prints.

A spray bar is positioned above the sand bed (red pipes). The media bed has 7 pipes running through it. The top layer is 3 feed pipes and the bottom has 4 return pipes.

The sand bed will be supported on a perforated PVC sheet incorporating some standoffs to support the spray bar. The plan is to have about 2" of water above the sand bed under normal operation.

The water levels are intended to allow either a small passive flow through the filter, or with the addition of a manifold and stand pipe, an active pumped flow, that can be controlled using float switches and pumps in the overflow chamber and filter return chamber. The return line from the filter bypasses the equipment chamber and discharges directly into the return chamber to (hopefully) preserve the zoo plankton from the filter.

I purchased enough Reborn media in advance to fill the bottom media compartment, but now I am thinking of using Pond Matrix instead and saving the Reborn for use in my CalRx. I have an A.E. ACR CalRx on hand that I will be using for supplementation, so I will not be using the media bed for that aspect. Besides, Reborn is so hard to get hold of these days, I should probably reserve it for CalRx use instead.

Let me know what you think.

Dennis

Looks great, are you using both sand and pond matrix as part of the controllable bed? Do you plan to have any redox and ph probes within the sand bend at all to monitor and control the O2 levels? some of the manufactured nitrate media can leech in anoxic water, @Lasse may wish to add to this, so maybe worth bearing that in mind depending on your anticipated O2 levels within the bed..

 

[Lasse]

Pumice (the material in Pond Matrix) contains silica. When I have used compounds containing silica in anaerobic environment - my Si concentrations in the water have reach ridicules concentrations. I would not recommend compounds containing silica in anaerobic environment. Pumice contain Al too

Sincerely Lasse

 

[Dennis Cartier]

Looks great, are you using both sand and pond matrix as part of the controllable bed? Do you plan to have any redox and ph probes within the sand bend at all to monitor and control the O2 levels? some of the manufactured nitrate media can leech in anoxic water, @Lasse may wish to add to this, so maybe worth bearing that in mind depending on your anticipated O2 levels within the bed..

Yes, the filter has a sand bed suspended over the media portion like the DyMiCo version I have modeled it on. I do plan to use an ORP probe in the process chamber of the filter that pumps water through the media. As I don't want the filter to become too aggressive in pulling the nitrate down too much, the redox reading will be used to modulate the flow through the filter and/or toggle an air stone in the process chamber to limit the ORP level and prevent the filter from moving on to the other elements after nitrate runs out. A common refrain I hear from people using these style of filters (DIY types, not the real ones), is that they have to discontinue carbon dosing and eventually increase flow and/or dose nitrate to prevent the filter from stripping it completely. I am hoping to intervene automatically before it comes to that.

I don't plan to place a PH probe within the filter itself as I don't plan to run CO2 and use the filter for supplementation.

Pumice (the material in Pond Matrix) contains silica. When I have used compounds containing silica in anaerobic environment - my Si concentrations in the water have reach ridicules concentrations. I would not recommend compounds containing silica in anaerobic environment. Pumice contain Al too

Sincerely Lasse

Ah, thanks Lasse. I did not know that Matrix also suffered from the silicate issue like Siporax. I guess I will just go with crushed coral then in the media bed.

Dennis

 

[Lasse]

I have not test pond Matrix but their SDS says 100% pumice and as I know it - pumice contain silica. Therefore the warning. I do not know i reality because I have not tested Pond Matrix

Sincerely Lasse

 

[Dennis Cartier]

I finally have my sump being constructed with the DyMico filter in it. You can see some photos of it in my build thread ( The Blue Window - 500 G in wall, never ending build). It should be complete in a couple of weeks.

It takes up 60% of the length of my sump. I hope it works, lol.

Dennis