I agree with mr Wilson, a few snaps at the general lay out would be nice, on the other side I was lookin to the link about the automatic water changer, IMO water changes should be automatized only at a point to have a couple of valves to empty an refill! But the salt mix and the should be carefully prepared by the aquarist in order to match the desired salinity or Ca values or other parameters that we could add in the water change.
Sorry just my two cents
By the way I own the ultimate aquariums by Paletta and I love the format! i also have the modern reef aquarium and in one of the volumes at the end there is a section about real life acuariums and its equipments, I think is a great way to learn about this hobby, as well as the TOTM every month in reefkeeping.com (sorry if this comment is a bit late but Mr Wilson brought it up a coiple of pages back)
Saludos from Mexico!!!!
... and I agree with Artur. There is no benefit to a hopper system that mixes saltwater because it is a simple process for the aquarist to safely carry out on their own. I also agree that inviting machines to take over potentially dangerous tasks like changing water invites the possibility of malfunction and subsequent disaster. I admittedly know nothing about the machine I posted, but no machine, or person, is infallible.
I advocate for a hybrid part man/part machine system. A manual valve should be controlled by the aquarist if and when a water change is deemed in order. If nothing else, this forces the aquarist to inspect the tank closely and possibly detect a problem the timer device will not. On the other hand, we can employ machines to safeguard our human error. Once a manual or valves are opened, a timer or metering device can be used so we don't forget that we have commenced the water change. It's sounds implausible, but the phone rings, your wife asks you to do something, or you wander off on your own leaving the tank filling and draining. Of course the machine is only as good as our programming prowess so the problem may still lie somewhere between the chair and the keyboard
The benefit of a manual water change is you can remove detritus with the water. There is a lot more "stuff" in detritus that has settled in your rock work, sump, and overflow box, than the amount of "stuff" in free flowing water in the system. The incoming water is typically a degree or two cooler so it will drop to the bottom or stay at one end of the display tank, making it easy to remove "old" water without taking some "new" water with it when filling and draining at the same time.
There are many ways to skin the water change cat. First you must mix the salt well, match the parameters (supplementing calcium or other elements may be necessary), match the temperature and make sure the water is well aerated with an air lift. Using a Metering pump to add the water is the safest method because it limits the maximum amount of water that one can add over a given period of time. The model I use moves a maximum of 8 gallons per day and can be dialed down to 2 GPD (the current peristaltic metering pump is too noisy, so I'm switching brands - maybe "Blue-White"
http://www.blue-white.com/ or an aquarium specific brand). If I forget to turn it off, It can't possibly add too much water; however, if you add the new water too slowly, it will affect salinity as it will interfere with freshwater evaporation top-off. The "new" water should enter in the overflow box, first compartment of the sump, or into a refugium so the water mixes well before entering the aquarium and reaching delicate corals. Sometimes chemicals fall out of solution when heated up or mixed with other water so a slow introduction is beneficial.
Alternatively, a solenoid valve (electronic valve) and mercury switch (electronic float switch) can be used to deliver the new water (via gravity feed or dedicated pump. A second (higher) solenoid shuts off the metering pump or solenoid when the desired water level is achieved. A secondary mechanical float valve mounted above the operating water level of the system is a good idea as an absolute fail-safe. A bulkhead that drains the sump if it overflows is your absolute - absolute fail-safe
A more common method for adding new water during a water change is to use a hobby pump (powerhead or external pump) so the task is done in a short period of time, minutes rather than days. This method makes it easier to focus on the task, but if you forget, things go bad quicker
You can use marker lines on your reservoir or a water meter to establish how much water you have added. I like to use a high volume mechanical float valve (livestock float valve
http://www.enasco.com/product/C12631N) at the end of the fill hose (in the sump) so it stops the flow when you reach a predetermined water level.
That covers adding the new water, now you need to remove the old water. It is more efficient to remove the old water first, before adding the new water, but make sure you don't drain more water than you can replace, or let the sump run dry and blast microbubbles into the tank. As I mentioned earlier, this is your opportunity to siphon or pump out detritus that has accumulated. You can fill a container (with water volume lines marked on it) with the old dirty water so you know how much you have removed. Once you've reached your target number of say 50 gallons (the size of a plastic shipping drum), you can stop and allow the system to continue filling until 50 gallons has been replaced. using two identical containers for holding & measuring new and old water makes it easier to know when to start and when to stop. A secret stash of new water is a good contingency plan.
The other "best way" of draining the old water out of your system is a passive method of simply allowing the extra water volume to overflow through a bulkhead mounted in the sump. With this method you only need to monitor and limit how much new water you are adding, as the draining is self regulating. What goes in, must come out. This is a K.I.S.S. method. You limit your input of new water by the amount available to add (your premixed 50 gallon drum). You eliminate any possibility of draining too much by letting gravity take care of that issue too. The return pump, closed loop pumps, and protein skimmer don't need to be adjusted or turned off so you don't invite the chance of failure on restart or forgetting to do so. The sump water level never lowers so you won't stir up detritus or send microbubbles into the display tank. The only down side is you don't export/remove detritus and you may lose some of your new water with the old. Because colder water sinks to the bottom, it is a good practice to add slightly cooler water so it doesn't float on the top and overflow out of your system through the drain standpipe or bulkhead.
Another common practice is to drain all or part of a sump or detritus settling drum and fill it back up to the original level with new water. This method limits detritus storms flowing from the sump to the display because the return pump is shut off during the process. In some cases, I go as far as to use a shopvac (wet vacuum) to remove sludge from the dark recesses of the sump. When you are done, let the dust (detritus) settle and turn the return pump back on. This is another area where we can employ timers as watchdogs for our own stupidity. Your aquarium controller will have several pump sequences that shut down for a predetermined amount of time. If your water change process takes half an hour, you can set the pump to come back on in an hour in case you forget to do so. Of course, this too invites the possibility of mechanical failure, so I prefer to use the alarm in my phone to remind me.
Peter, you have made a wise choice with the illuminated power outlets, as this visual aid limits the dangling cord or controller bypass you may overlook. For those of you who don't want to spend a lot of money on such an elaborate electrical system, there are some cheap illuminated plug adapters and power bars with individual illuminated switches. AC/DC night lights (no, not the ones with the Angus Young schoolboy outfit
) are also a good addition because they light up and catch your attention when the outlet has shut off. Another low tech trick is to plug in a clock that will be behind by however many hours the power was off for. Often, the power goes off for a short period of time, and the aquarist isn't even aware of it. Once you know, you can trouble shoot your system and take appropriate action.
Having said all that... peristaltic metering pumps like the one I linked earlier and aquarium controllers are very reliable. These pumps cannot possibly start a siphon, or pump faster than the preset rate. It likely uses one motor to both add and subtract water so the quantities should be bang on. These types of pumps are used in high tech industry and for medical purposes so they have to be reliable. I'm not about to say a Jerry rigged daisy chain of DIY devices is more reliable. I just agree with Artur's opinion that you can't completely remove the human element, no matter how flawed (not directed at you specifically Peter)
