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3002 Views 45 Replies 7 Participants Last post by  PAUL GRAHAM
I haven't been active here for some time. Thought I'd drop in. My 200 gallon jungle style system is doing well and I'd like to show it off a bit.

Although this is a high-tech system with inert base substrate, I owe much to Diana Walstad and her Ecology of the Planted Aquarium.

Current parameters

pH: 6.75
ORP: 509 mV
TDS: 280 ppm
NO3: 15 ppm
PO4: 1.4 ppm
K: 35 ppm
Fe: 0.13 ppm
dKH: 5.6
dGH: 3.4
Ca: 16.0 ppm
Mg: 4.9 ppm
Ca/Mg: 3.3
CO2: 29.9 ppm
DO: 9 ppm peak

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That's pretty much it. If the plants have sufficient light and are not nutrient limited, and the number of plants is high enough, DO should peak at or above 100% saturation every day. If this level of oxygenation persists over time, the system redox will typically settle to a fairly high value and will be stable. DOM is largely reducing so will tend to depress the ORP value. Therefore, exporting DOM is a part of maintaining this stability. The single most effective device for this is water changes of adequate size and frequency.

I am an advocate for high capacity biological filtration and not for nitrification alone. A healthy and complete bio-filter also fosters robust populations of heterotrophs that process DOM. I have 12 gallons of bio-media directly in the circulation loop. It's a large community of aerobic organisms and all these must have their O2. The system and the plants support this bio-filter and still I get 100% O2 every day. DOM is decomposed thoroughly and the ORP remains high.

This is the reason it is useful to observe the ORP. Pinning down the actual absolute value for ORP is not as important as detecting changes. That said, it is desirable to have a relatively high redox. The Apex ORP monitor logs data and produces a continuous graphic trace so I can spot trends at a glance, but it reads high compared to the American Marine Pinpoint ORP monitor. Neptune Systems does not insist on calibrating the probe but suggests that a specific two-point procedure is possible if you wish to do so. This calibration is something of a fiddly affair and is, to me, not worth the effort. The graphic is far more helpful than the numbers, so I really don't care. The Pinpoint has one-point calibration which is necessary if you want a number that you can believe is at least close to the real redox value. Mid-day in my system, the Pinpoint jumps around inside the range 380 mV to 420 mV while the Apex is reporting 530 mV. I believe the numerical value from the Pinpoint and this is a very respectable redox.

ORP = 400 mV is entirely possible with a lot of healthy plants and good DOM management.
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Another question.

I'm considering plumbing in what is essentially a spindown filter (or two; each with different mesh size) with a valve at the bottom. The valve would be on a timer and open for a brief period of time once a day. Basic idea would be to flush detritus caught in the spindown filter to keep it from reaching the FX4 and FX6 I have. I'd want it to open and drain through a 1/4" line for only enough time to drain the reservoir and clear out the junk trapped by the steel mesh filter.

Can you run something like that with an Apex controller?
Anything that is controlled electrically can be used in Apex. An event that is caused by turning operating power ON or OFF can be initiated by changing the corresponding state of an electrical outlet dedicated to that event. The Apex Energy Bar is a bank of relays that are independently controlled. An EB832 has 8 outlets, each of which can control whatever event you need to make happen according to the program you devise. They are remote-control switches. These are 120 VAC relays, each outlet having a maximum current rating. The EB832 also has two 24 VDC switched power supplies for two additional functions that work on that voltage, such as small utility pumps or solenoid operated valves. The energy bar has one AC power input and an overall maximum current rating. If 8 outlets isn't enough you can add 8 more with an EB8 (or 4 more with an EB4). One Apex base unit, the central controller, can handle a really big system.

You can switch solenoid valves, lights, chillers, sterilizers, heaters, circulation pumps, powerheads, anything that runs on 120 VAC, as long as the ampere draw does not exceed the current rating of its outlet. So, you dream up an application that involves any such electrical load and Apex can do that for you.

The input to the Apex to control the status of an outlet can be a timer you may program for any event length and frequency; status condition of a shunting switch; status condition of another outlet in the system; or threshold of a value for a parameter such as temperature or pH. You can increase input capabilities by adding modules to support the additional probes. The communication between the base unit and the Energy Bars is via the Aquabus (looks like a USB cable - various lengths available). The modules and Energy Bars are just daisy-chained by any convenient wiring path. It's plug-and-play; the base unit automatically assigns the system address to each module. All you do is hook it up, enable the inputs, and program the outlets.

Programming an outlet is done with a simple IF-THEN instruction set in plain language. Each outlet has a dashboard icon that shows its present state and that may also be used as a manual switch to over-ride its present state. You can name the outlets and the inputs to suit your preferences (character limits apply).

Examples next post.
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In this example, a 300 watt heater is plugged into Outlet #4 on the Energy Bar4 at system address 12. Its normal state is OFF. It turns ON if the thermometer (input TEMP) drops below 77, and then OFF when the thermometer rises above 77. The manual thermostat on the heater is set at 80. The circulation pump is plugged into another outlet (Output) in the system. If that outlet is turned OFF, the heater will not turn ON. This prevents overheating the heater module when water is not passing through. This conditional is also used for the UV sterilizer and the CO2 solenoid.

Here is a timer program for the daily dose of potassium carbonate. The peristaltic pump is plugged into Outlet #1 on the Energy Bar 8 at system address 14. The Apex will see an ON state for as long as the system clock registers 06:00 through 06:01 for a total of 2 minutes (120 seconds), but there is a DEFER conditional, which can be programmed for minutes and seconds, that forces a wait in actual turn-on of power for 30 seconds. So the actual dosing time is 90 seconds. The dose rate for any supplement can be adjusted simply by altering the timer program. The Apex operates in 24 hour time.

Here is the control for keeping the RO/DI reservoir topped up. The input in this case is a float switch named RESFUL, in which up-float is the open-circuit position. Until the waterline rises sufficiently to float the switch it will be in closed-circuit position, and the program will keep the raw-water supply solenoid valve, named ROSOL, turned ON (valve open). The ROFLUSH outlet is another solenoid valve that opens a by-pass around the flow restrictor which washes the membrane. It is necessary to have raw-water supply ON to do this, so this ensures that ROSOL will be switched ON with ROFLUSH. ROFLUSH is on a 10 minute timer program beginning at 09:00 daily.

There's more. You can do neat tricks with virtual outlets. You can set up alarm responses to any condition which Apex can recognize. Apex is a very good pH controller. You would not need any additional timers.

Here is a screenshot of the dashboard (partial) just to give you the idea of how it presents on your computer. This is an older configuration and details have changed, but this is what your dashboard will look like.

Some thought should go into power distribution and conditioning. I have a fairly elaborate power system dedicated to the aquarium involving voltage regulation, filtering, and transient suppression. The whole thing is backed up by the generator. There is a lot riding on protecting this equipment from damage and keeping it functioning through blackouts.
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Can you run something like that with an Apex controller?
Well, I'm guessing after all that you can imagine how to use the Apex to accomplish this drain function. You can do this by connecting a solenoid valve to any timer. Solenoid valves for 1/4" line are common. Neptune Systems has one that can be purchased with its own 24 VDC power supply. So you wouldn't need an Apex for this, but it will do other cool things as well
Friday, 5/26, mechanical filters changed, bio-media rinsed, and 12% water changed. The SWCR operates in the background as usual. ORP reported by Pinpoint rose to 500 mV and there is a corresponding ascent in the Apex ORP trace as well. There is a strong suggestion here that a "big gulp" water change has a marked impact on DOM. I have noted that correlation for a long time now, although it was not always so pronounced (though it was not always as much as 12% either). Since revising the engineering I am consistently drawing 12% and made bio-media rinse a regular part of the routine. I believe this to be essential based on the redox data.

The bio-media is of two kinds: a porous solid composed of standard Sera Siporax and SeaChem Matrix; and open-frame Coralife 1" bio-balls. Media bags are extra-large and packed very loosely so that they are sufficiently flaccid to conform to the canisters, minimizing bypass. Rinsing these bags is just a thorough dunking in the last four gallons of discard from the water change. Judging by the brown turbidity there is considerable POM accumulating despite the 25 micron polish. Without thoroughly rinsing the media these canister filters turn into DOM generators. This maintenance cycle most definitely must be on a two-week schedule.

Today's numbers

pH: 6.75
TDS: 340 ppm
NO3: 13 - 18 ppm
PO4: 2.50 ppm
K: 30 ppm
Fe: 0.14 ppm
dKH: 5.5 (99 ppm)
CO2: 26.8 ppm
dGH: 4.3 (76 ppm)
Ca: 16.8 ppm
Mg: 8.3 ppm
Ca/Mg: 2.0

Parameters are at target values and stability is excellent. Dosing rates and SWCR are balancing nicely.
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