Review on 🐠 AQQA Submersible Fish Tank Heater – Intelligent LED Display, External Thermoregulation – Ideal for Betta Fish Tank, Turtle Tank – Available in 15W, 25W, 50W, 75W, 100W by Sander Savala

I have a 20 gallon AIO seawater tank and need a small heater that fits in one of the chambers in the rear of the tub. Unfortunately there is only about 8 inches of vertical space, not enough for most 75+W tubular heaters. I took a chance in choosing this AQQA heater and I'm glad I did. multiple temperature sensors in different parts of the tank. The tank is still running so I can play around with the sensor placement and temperature settings a bit. I have tested and calibrated these sensors to the best of my knowledge and I guarantee they are 1 degree Fahrenheit. I also have to say that this AQQA heater is now the third heater I've tried in this tank, having been disappointed with the other two I bought because they were extremely inaccurate and had a hard time finding one maintain constant temperature. I also connected AQQA to a smartstrip that shows me real-time power consumption. I bought the 75w version of this heater and was a bit surprised to see that it actually draws 108w. However, it turns on and off with different on and off periods. Depending on how much you need to heat the water. If I set it to heat the water a few degrees from its location, the heater would heat for 60 seconds, then stop heating for 120 seconds, then repeat the same cycle. Once the water reached the right temperature, the cycle was more like a 40 second heat and a 4 minute stop. This heater is very slow, which isn't necessarily a bad thing. In one case I set it to increase the temperature of the tank by 1 degree and it took over 4 hours to get to that temperature. It also means there are no sudden temperature changes, which is good. I'm including one of my sensor readings from the last 6 hours to show how consistent the temperature is when the tank reaches the set temp. These temperature measurements are taken every 10 seconds. Now for the reason this heater is losing a star: The temperature reading on the heater itself is way too high. The heater is currently set to 80 and says my water is 80 even though my water is only 75.5-76 degrees depending on where I measure in the tank. I know many other heaters have similar inaccuracies, so be careful with your temperature setting and rely on other thermometers to get a better idea of how warm the water really is. Once you know how far away your particular heater is, it's easy to compensate since in my case setting it to 80 actually means about 76. Oh, and I have a temp gauge right next to the heater so I know what the water is near The heater is nowhere near 80 either. My temp chart for this sensor is a sawtooth pattern with the heater turning on and off, but the peak temp with the heater on is a little under 77, and when the heater is off it climbs to just under 76. Another downside that I know has been documented on the product page is the very short cord. I see this as an advantage for smaller desktop aquariums, but it's a bit limiting in my case and I'll probably need to use an extension cord once I've straightened my cords. So just keep that in mind. I love the form factor of this heater and am surprised that so many long tube heaters still exist. I think these curved tubes make sense for many tanks.