FZONE Pro Series Aquarium Dual Stage CO2 Regulator - Adjustable Output Pressure with DC Solenoid, High Precision Needle Valve & Bubble Counter - Perfect for Planted Tanks & Aquascaping

I have been involved in the aquarium hobby for several decades, but this is the first time I have ventured into the use of CO2 injection for a planted aquarium. I have a 55 gallon freshwater tank that is heavily planted and moderately stocked with fish. I have adequate lighting and add fertilizers to the tank, but needed a source of carbon to facilitate plant growth. After extensive research into various options, I decided to use CO2 injection from a standard 5# CO2 tank, FZONE regulator and a ceramic diffuser.I chose the FZONE Pro Dual-stage regulator for a number of specific reasons.1. This regulator comes with a standard CGA320 connector that screws onto standard CO2 tanks like the 5# tank I chose. Should you wish to use this regulator with smaller tanks such as paintball tanks, Soda Stream tanks, or even disposable tanks, adapters are available to do so. However, for a 55 gallon tank and larger, standard CO2 tanks are more cost effective.2. The regulator comes with two stages of regulation and two gauges to monitor tank pressure and delivery pressure. Furthermore, the delivery pressure is adjustable. The dual stage regulator keeps the delivery pressure constant and avoids the possibility of a end of tank surge of CO2 which can harm livestock in the tank. Thus, I do not have to monitor tank pressure on a daily basis. Many regulators come with two gauges but are only a single stage of regulation. Some mini regulators come with only one gauge. Some regulators come with a non-adjustable delivery pressure.3. The regulator comes with a solenoid that operates on a 12v DC power supply. That is safer than a 120V solenoid when you are working near water. If the power supply does fail, it is easily replaced as 12 VDC power supplies are commonly used for a variety of applications. I have the power supply plugged into a timer such that the CO2 comes on 2 hours before my lighting in the morning and turns off 1 hour before the lights turn off. That insures the plants have an adequate supply of CO2 during the high-growth period, but CO2 does not build up to excessive levels at night when plants cannot consume it. The solenoid does cut off the CO2 flow completely when the power is off.4. The regulator comes with not just one, but two needle valves and accompanying bubble counters with check valves built in. These appear to be precision machined valves that provide precise control over the CO2 flow. They seem to be quite stable in that when the CO2 comes on in the morning, the flow rate is the same as it was the previous day. I have mine set for about 90 bubbles per minute, but you might need more or less depending upon your tank size, water chemistry and plant requirements. I am only using one of the needle valves, but you can connect a second tank, or reserve it as a spare in case the first one fails.The check valve insures that tank water does not back up into the needle valve and regulator when the CO2 flow is stopped at night. This avoids one potential maintenance issue.5. When I had my CO2 tank filled, the supplier provided a couple of nylon washer. However, I found that these washer were not thick enough to provide a good seal between the tank and the regulator. The thicker washer provided with the regulator worked perfectly.6. I have not had the unit long enough to verify its long term durability, but considering I should only have to refill the CO2 tank every 4-6 months and I do not have to make routine adjustments to the needle valve, I predict that the system will last a long time. The most likely maintenance issues may be the solenoid and power supply; both of these are easily replaceable should the need arise.7. Lastly, the system seems to be fairly priced. Most dual-stage regulators are significantly more expensive than the FZONE. Since I have not used CO2 injection previously, I did not want to spend $200-300 for a regulator alone.I do recommend this unit to anyone with a 40 gallon and larger tank who wants to begin using CO2 injection. For tanks smaller than 40 gallons, this is probably more system than is required, but it suits my 55 gallon setup quite well.