Quick question about safe placement of heating elements. I have a 500W heater that I plan to use as main and a 350W I plan to use as a backup. The 500W can only fit in the sump if I sit it horizontally as shown in the attached image. The height on the end of the heating element that would sit off the floor of the sump is around 5 inches... i plan to keep the water level in the sump higher than that by a few inches. Is this safe ?